Western Australia`s Mothers and Babies 2012

Western Australia`s Mothers and Babies 2012
Statistical series number 100
ISSN: 0816-2999
Western Australia’s
Mothers and Babies, 2012
30th Annual Report of the Western Australian
Midwives’ Notification System
May 2015
health.wa.gov.au
October 2014
Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Western Australia’s Mothers and Babies, 2012
30th Annual Report of the
Western Australian Midwives’ Notification System
May 2015
Maternal and Child Health Unit
Data Integrity Directorate
Resourcing and Performance
Department of Health, Western Australia
Statistical series number 100
ISSN: 0816-2999
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Acknowledgements
The authors wish to thank all midwives for continuing to provide high quality data to the
Western Australian Maternal and Child Health Unit for all births in Western Australia.
The completeness and accuracy of the data is dependent upon their dedication.
Appreciation is also acknowledged for the contribution of:
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Mrs Daelene Johnson, Mrs Maureen Cheong and other Maternal and Child Health
Unit staff who process and validate these data;
Mrs Vivien Gee - Principal Consultant, Statutory Mortality Committees for providing
information on Perinatal Mortality;
The staff at Western Australia Data Linkage Branch;
The Hospital Morbidity Data Collection staff for their support in the validation
processes and provision of data this report;
The Registry of Births, Deaths and Marriages for assisting with ensuring the
completeness of the collections for births and perinatal deaths in Western Australia
via the Western Australia Data Linkage Branch.
Women who provided consent for their images and images of their children to be
used for health publications. One of these images have been used on the front page
of this report.
Further information
Enquiries or comments on this publication and/or requests for additional information
should be addressed to:
Manager, Maternal and Child Health Unit
Statutory and Non-Admitted Branch
Data Integrity Directorate
Resourcing & Performance
Department of Health, Western Australia
189 Royal Street
EAST PERTH WA 6004
Telephone: (08) 9222 2417
Facsimile: (08) 9222 4408
Email:
[email protected]
Internet:
http://www.health.wa.gov.au/healthdata/statewide/midwives.cfm
Citation
The citation below should be used in reference to this publication.
Hutchinson, M. (2015). Western Australia’s Mothers and Babies, 2012: 30th Annual
Report of the Western Australian Midwives’ Notification System, Department of Health,
Western Australia.
ii
Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Table of Contents
Acknowledgements ................................................................................................................................ ii
Further information ................................................................................................................................. ii
Citation ................................................................................................................................................... ii
Table of Contents .................................................................................................................................. iii
List of Tables ......................................................................................................................................... vi
List of Figures .........................................................................................................................................x
Executive summary ................................................................................................................................... xi
Maternal demographics ......................................................................................................................... xi
Place of birth.......................................................................................................................................... xi
Tobacco smoking during pregnancy ..................................................................................................... xi
Pregnancy Profile ................................................................................................................................. xii
Labour and Birth ................................................................................................................................... xii
Aboriginal Mothers .............................................................................................................................. xiii
Aboriginal infants ................................................................................................................................. xiv
All Infants ............................................................................................................................................. xiv
Perinatal Mortality ................................................................................................................................. xv
1.
Introduction ....................................................................................................................................... 1
1.1. Changes to report format and content .......................................................................................... 1
1.2. Legal status of perinatal statistics in Western Australia ............................................................... 1
1.3. Midwives’ Notification System ...................................................................................................... 2
1.4. Aboriginal status ........................................................................................................................... 2
1.5. Presentation of data in report ....................................................................................................... 3
1.6. Data provision model for Midwives’ Notification System - 2012 ................................................... 4
1.7. Data Sources for the 2012 birth data ............................................................................................ 4
2.
Mothers ............................................................................................................................................. 5
2.1. Maternal demographics ................................................................................................................ 6
2.1.1.
Maternal age .................................................................................................................... 6
2.1.2.
Place of Residence .......................................................................................................... 7
2.1.3.
Country of birth ................................................................................................................ 8
2.1.4.
Marital status ................................................................................................................... 9
2.1.5.
Place of birth .................................................................................................................. 10
2.1.6.
Place of birth event ........................................................................................................ 12
2.1.7.
Smoking tobacco during pregnancy .............................................................................. 14
2.1.8.
Socio-economic status .................................................................................................. 18
2.2. Pregnancy profile ........................................................................................................................ 19
2.2.1.
Maternal Weight............................................................................................................. 19
2.2.2.
Parity .............................................................................................................................. 21
2.2.3.
Pregnancy gestation at first antenatal care visit ............................................................ 23
2.2.4.
Number of antenatal care visits during pregnancy ........................................................ 24
2.2.5.
Medical conditions ......................................................................................................... 25
2.2.6.
Medical conditions and obesity...................................................................................... 25
2.2.7.
Complications of pregnancy .......................................................................................... 26
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
2.2.8.
Complications of pregnancy and obesity ....................................................................... 27
2.2.9.
Procedures and treatments ........................................................................................... 28
2.3. Labour ......................................................................................................................................... 29
2.3.1.
Onset of labour .............................................................................................................. 29
2.3.2.
Augmentation of labour ................................................................................................. 30
2.3.3.
Methods of augmentation .............................................................................................. 31
2.3.4.
Induction of labour ......................................................................................................... 33
2.3.5.
Induction of labour by maternity service ........................................................................ 35
2.3.6.
Analgesia ....................................................................................................................... 36
2.4. Anaesthesia ................................................................................................................................ 37
2.5. Fetal presentation ....................................................................................................................... 40
2.5.1.
Vertex presentation and method of birth in maternity services ..................................... 41
2.6. Method of birth ............................................................................................................................ 42
2.6.1.
Caesarean section by maternity service ....................................................................... 44
2.7. Hours of established labour ........................................................................................................ 45
2.8. Complications of labour and birth ............................................................................................... 46
2.8.1.
Plurality of pregnancy .................................................................................................... 46
2.8.2.
Obesity........................................................................................................................... 47
2.8.3.
Primary postpartum haemorrhage ................................................................................. 48
2.8.4.
Reason for caesarean section ....................................................................................... 49
2.8.5.
Accoucheur .................................................................................................................... 49
2.9. Repair of perineum and/or vagina .............................................................................................. 50
3.
Aboriginal mothers and infants ....................................................................................................... 52
3.1. Maternal age ............................................................................................................................... 52
3.1.1.
Age-specific birth rates .................................................................................................. 54
3.2. Health region of residence .......................................................................................................... 56
3.3. Care during pregnancy ............................................................................................................... 58
3.4. Previous pregnancies ................................................................................................................. 59
3.5. Smoking tobacco during pregnancy ........................................................................................... 61
3.6. Complications of Pregnancy ....................................................................................................... 63
3.7. Medical conditions before pregnancy ......................................................................................... 65
3.8. Procedures and treatments ........................................................................................................ 66
3.9. Labour and birth details .............................................................................................................. 67
3.9.1.
Onset of labour .............................................................................................................. 67
3.9.2.
Place of birth .................................................................................................................. 67
3.9.3.
Method of birth ............................................................................................................... 69
3.9.4.
Complications of labour or birth ..................................................................................... 69
3.10. Trauma to perineum and/or vagina ............................................................................................. 71
3.11. Infants born to Aboriginal women ............................................................................................... 72
3.11.1.
Crude birth rate .............................................................................................................. 74
3.11.2.
Birthweight and gestational age .................................................................................... 75
3.11.3.
Birthweight ..................................................................................................................... 76
3.11.4.
Risk of Low Birthweight ................................................................................................. 78
3.11.5.
Low birthweight and place of residence ........................................................................ 79
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
3.12. Aboriginal status of infant ........................................................................................................... 80
4.
Infants ............................................................................................................................................. 81
4.1. Metrics of infants born................................................................................................................. 81
4.1.1.
Crude birth rate .............................................................................................................. 81
4.1.2.
Plurality .......................................................................................................................... 82
4.1.3.
Gender ........................................................................................................................... 83
4.1.4.
Gestational age.............................................................................................................. 84
4.1.5.
Gestational age, birthweight and plurality ..................................................................... 85
4.1.6.
Birthweight centiles ........................................................................................................ 86
4.1.7.
Birth status and place of birth of preterm infants ........................................................... 87
4.1.8.
Birthweight ..................................................................................................................... 90
4.1.9.
Birth status and place of birth ........................................................................................ 92
4.1.10.
Plurality of infants born .................................................................................................. 93
4.1.11.
Plurality, presentation and birth method ........................................................................ 94
4.2. Infant extra-uterine adjustment ................................................................................................... 95
4.2.1.
Apgar score at one minute and five minutes ................................................................. 95
4.2.2.
Infant resuscitation ........................................................................................................ 97
4.3. Birth trauma ................................................................................................................................ 98
4.4. Birth defects ................................................................................................................................ 98
4.5. Infant outcome ............................................................................................................................ 99
5.
6.
4.5.1.
Admission to Special Care Nursery ............................................................................... 99
4.5.2.
Transfer from birth place ............................................................................................. 100
4.5.3.
Liveborn infant length of stay at birthplace .................................................................. 103
Perinatal Mortality ......................................................................................................................... 104
5.1.1.
Perinatal mortality by gestational age in WA ............................................................... 105
5.1.2.
Perinatal mortality by birthweight in WA ...................................................................... 105
References .................................................................................................................................... 108
Appendix A: Glossary ............................................................................................................................ 109
Appendix B: Supplementary Tables ...................................................................................................... 113
Appendix C: Notification of case attended form Jan-Jun 2012 ............................................................. 121
Appendix C: Notification of case attended form Jul-Dec 2012 .............................................................. 122
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
List of Tables
Table 1: Aboriginal status of women who gave birth in WA, 2012 .................................................................. 5
Table 2: Age of women who gave birth in WA, 1980-2012 ............................................................................. 6
Table 3: Place of residence of women who gave birth in WA, 2012 ............................................................... 7
Table 4: Country of birth of women who gave birth in WA, 2012 .................................................................... 8
Table 5: Trend of country of birth of women who gave birth in WA, 2008-2012 ............................................. 9
Table 6: Marital status and plurality of women who gave birth in WA, 2012 ................................................... 9
Table 7: Place of birth of metropolitan women who gave birth in WA, 2012 ................................................. 10
Table 8: Place of birth of country women who gave birth in WA, 2012 ......................................................... 11
Table 9: Place of birth and intended place of birth of women who gave birth in WA, 2012 .......................... 12
Table 10: Place of birth and plurality of women who gave birth in WA, 2012 ............................................... 14
Table 11: Smoking and age of women who gave birth in WA, 2012 ............................................................. 16
Table 12: Smoking tobacco and country of birth of women who gave birth in WA, 2012 ............................. 17
Table 13: Socio-economic status and age of women who gave birth in WA, 2012 ...................................... 19
Table 14: Body mass index and age of women who gave birth WA, 2012 ................................................... 20
Table 15: Previous infants and age of women who gave birth in WA, 2012 ................................................. 21
Table 16: Gestation at first antenatal care visit of women who gave birth in WA, 2012 ............................... 23
Table 17: Trends for gestation at first antenatal care visit for women who gave birth in WA, 20102012................................................................................................................................................ 24
Table 18: Number of antenatal care visits attended by women who gave birth in WA, 2012 ....................... 24
Table 19: Selected pre-existing medical conditions by plurality of pregnancy of women who gave
birth in WA, 2012 ............................................................................................................................ 25
Table 20: Selected pre-existing medical conditions by obesity of women who gave birth in WA,
2012................................................................................................................................................ 25
Table 21: Selected complications of pregnancy by plurality of pregnancy for women who gave birth
in WA, 2012 .................................................................................................................................... 26
Table 22: Selected pregnancy complications by obesity in women who gave birth in WA, 2012 ................. 27
Table 23: Procedures and treatments provided to women who gave birth in WA, 2012 .............................. 28
Table 24: Onset of labour and plurality of pregnancy for women who gave birth in WA, 2012 .................... 29
Table 25: Labour, augmentation and method of birth for women who gave birth in WA, 2012 .................... 30
Table 26: Augmentation of spontaneous labour and hours of labour for women who gave birth in
WA, 2012 ........................................................................................................................................ 31
Table 27: Trend of prostaglandin as augmentation method of spontaneous labour and hours of
labour for women who gave birth in WA, 1998 - 2012 ................................................................... 32
Table 28: Induction method, birth method for women who gave birth in WA, 2012 ...................................... 33
Table 29: Trend of prostaglandin as induction method and hours of labour for women who gave
birth in WA, 1998 - 2012 ................................................................................................................ 34
Table 30: Induction of labour by maternity service of women who gave birth in WA, 2012 .......................... 35
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Table 31: Analgesia during labour and method of birth for women who gave birth in WA, 2012 ................. 36
Table 32: Analgesia for women who had vaginal births in WA, 2012 ........................................................... 36
Table 33: Anaesthesia and method of birth for women who gave birth in WA, 2012 ................................... 37
Table 34: Anaesthesia for women who had vaginal births in WA, 2012 ....................................................... 38
Table 35: Anaesthesia for women who had birth by caesarean section in WA, 2012 .................................. 38
Table 36: Trend for anaesthesia for women who gave birth by caesarean section in WA, 1986-2012 ........ 39
Table 37: Fetal presentation and method of birth for singleton infants born in WA, 2012 ............................ 40
Table 38: Method of birth and maternity service of infants born with vertex presentation in WA,
2012................................................................................................................................................ 41
Table 39: Method of birth and plurality of pregnancy for women who gave birth in WA, 2012 ..................... 42
Table 40: Method of birth by history of caesarean section for women who gave birth in WA, 2012 ............ 43
Table 41: Caesarean section by maternity service of women who gave birth in WA, 2012 ......................... 44
Table 42: Onset of labour by hours of labour for women who gave birth vaginally in WA, 2012 .................. 45
Table 43: Complications of labour and birth by plurality of pregnancy for women who gave birth in
WA, 2012 ........................................................................................................................................ 46
Table 44: Complications of labour and birth by obesity in women who gave birth in WA, 2012 ................... 47
Table 45: Frequent complications of labour and birth for women who gave birth by caesarean
section in WA, 2012 ....................................................................................................................... 49
Table 46: Method of birth and accoucheur for women who gave birth in WA, 2012 ..................................... 49
Table 47: Method of birth and perineal status for women who gave birth in WA, 2012 ................................ 50
Table 48: Aboriginal status of women who gave birth in WA, 2012 .............................................................. 52
Table 49: Maternal age summary statistics and Aboriginal status for women who gave birth in WA,
2012................................................................................................................................................ 52
Table 50: Maternal age and Aboriginal status of women who gave birth in WA, 2012 ................................. 52
Table 51: Maternal age-specific birth rates by Aboriginal status of women who gave birth in WA,
2012................................................................................................................................................ 54
Table 52: Health region of residence and Aboriginal status of women who gave birth in WA, 2012 ............ 57
Table 53: Gestation at first antenatal care visit and Aboriginal status of women who gave birth in
WA, 2012 ........................................................................................................................................ 58
Table 54: Gestation at first antenatal care visit, Aboriginal status and health region of residence of
women who gave birth in WA, 2012 ............................................................................................... 59
Table 55: Number of previous infants and Aboriginal status of women who gave birth in WA, 2012 ........... 59
Table 56: Previous caesarean section and Aboriginal status of women who gave birth in WA, 2012 ......... 60
Table 57: Number of previous infants who died and Aboriginal status of women who gave birth in
WA, 2012 ........................................................................................................................................ 61
Table 58: Tobacco smoking and Aboriginal status of women who gave birth in WA, 2012 .......................... 61
Table 59: Tobacco smoking, health region of residence and Aboriginal status of women who gave
birth in WA, 2012 ............................................................................................................................ 62
Table 60: Change in tobacco smoking during pregnancy by Aboriginal women who gave birth in
WA, 2012 ........................................................................................................................................ 62
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Table 61: Complication of pregnancy, health region of residence and Aboriginal status of women
who gave birth in WA, 2012 ........................................................................................................... 63
Table 62: Complications of pregnancy and Aboriginal status of women who gave birth in WA, 2012 ......... 64
Table 63: Pre-existing medical conditions and Aboriginal status of women who gave birth in WA,
2012................................................................................................................................................ 65
Table 64: Procedures, treatments and Aboriginal status of women who gave birth in WA, 2012 ................ 66
Table 65: Onset of labour and Aboriginal status of women who gave birth in WA, 2012 ............................. 67
Table 66: Place of birth and Aboriginal status of women who gave birth in WA, 2012 ................................. 67
Table 67: Method of birth and Aboriginal status for women who gave birth in WA, 2012 ............................. 69
Table 68: Complications of labour or birth and Aboriginal status of women who gave birth in WA,
2012................................................................................................................................................ 70
Table 69: Perineal status and Aboriginal status for women who gave birth vaginally in WA, 2012 .............. 71
Table 70: Birth status and maternal Aboriginal status for infants born in WA, 2012 ..................................... 72
Table 71: Birth status, maternal residence and maternal Aboriginal status for infants born in WA,
2012................................................................................................................................................ 73
Table 72: Trends for crude birth rate and maternal Aboriginal status for infants born in WA, 19832012................................................................................................................................................ 74
Table 73: Gestational age and birthweight for infants born to Aboriginal mothers in WA, 2012 ................... 75
Table 74: Birthweight and maternal Aboriginal status for infants born in WA, 2012 ..................................... 76
Table 75: Trends for birthweight and maternal Aboriginal status for infants born in WA, 1980-2012 ........... 77
Table 76: Trends for Relative Risk of low birthweight and maternal Aboriginal status for infants born
in WA, 1980-2012........................................................................................................................... 78
Table 77: Birthweight and maternal Aboriginal status for infants born alive in WA, 2012 ............................. 79
Table 78: Low birthweight, maternal residence and maternal Aboriginal status for infants born alive
in WA, 2012 .................................................................................................................................... 79
Table 79: Infant Aboriginal status and maternal Aboriginal status for infants born in WA, 2012 .................. 80
Table 80: Trends for birth status and crude birth rate for infants born in WA, 1980-2012 ............................ 81
Table 81: Plurality of birth and maternal Aboriginal status for infants born in WA, 2012 .............................. 82
Table 82: Birth status and gender for infants born in WA, 2012.................................................................... 83
Table 83: Gestational age and birth status for infants born in WA, 2012 ...................................................... 84
Table 84: Gestational age and birthweight for single birth infants born in WA, 2012 ................................... 85
Table 85: Gestational age and birthweight for multiple birth infants born in WA, 2012 ................................ 85
Table 86: Gestational age and birthweight for infants born in WA, 2012 ...................................................... 86
Table 87: Birth status and place of birth of infants born at 23 to 31 weeks gestation in WA, 2012 .............. 87
Table 88: Trends for birth status and place of birth of infants born at 23 to 31 weeks gestation in
WA, 1986-2012 .............................................................................................................................. 88
Table 89: Birthweight and birth status for infants born in WA, 2012 ............................................................. 90
Table 90: Birthweight and resuscitation for infants born alive in WA, 2012 .................................................. 91
Table 91: Birth status and place of birth for infants born in WA, 2012 .......................................................... 92
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Table 92: Birth status and plurality of birth for infants born in WA, 2012 ...................................................... 93
Table 93: Fetal presentation, method of birth and plurality of birth for infants born in WA, 2012 ................. 94
Table 94: Apgar score at one minute and time to spontaneous respiration for infants born alive in
WA, 2012 ........................................................................................................................................ 95
Table 95: Apgar score at five minutes and time to spontaneous respiration for infants born alive in
WA, 2012 ........................................................................................................................................ 96
Table 96: Resuscitation received by infants born alive in WA, 2012 ............................................................ 97
Table 97: Resuscitation and Apgar score at five minutes for infants born alive in WA, 2012 ....................... 97
Table 98: Birth trauma to infants born in WA, 2012 ...................................................................................... 98
Table 99: Length of stay in Special Care Nursery and plurality of birth for infants born alive in WA,
2012................................................................................................................................................ 99
Table 100: Transfer from birth place to other hospital for infants born alive in WA, 2012 .......................... 100
Table 101: Length of stay at birth site before discharge home by birthweight for infants born alive in
WA, 2012 ...................................................................................................................................... 101
Table 102: Length of stay at birth site before discharge home by gestation for infants born alive in
WA, 2012 ...................................................................................................................................... 102
Table 103: Length of stay at birth site by gestation for infants who were transferred from birth or
died in WA, 2012 .......................................................................................................................... 102
Table 104: Perinatal mortality and maternal Aboriginal status for infants born in WA, 2012 ...................... 104
Table 105: Trends for perinatal mortality by maternal Aboriginal status for infants born in WA, 19942012.............................................................................................................................................. 105
Table 106: Perinatal mortality by gestation for infants born in WA, 2012 ................................................... 105
Table 107: Perinatal mortality by birthweight for infants born in WA, 2012 ................................................. 105
Table 108: Birthweight for infants that died in perinatal period and were born in WA, 2012 ...................... 106
Table 109: Perinatal mortality and plurality of birth for infants born in WA, 2012 ....................................... 106
Table 110: Age at neonatal death for infants born in WA, 2012 ................................................................. 106
Table 111: Autopsy requests for infants that died in perinatal period in WA, 2012..................................... 107
Table 112: Causes of perinatal death for infants born in WA, 2012 ............................................................ 107
Table 113: Trend for age-specific birth rates and Aboriginal status for women who gave birth in
WA, 1983-2012 ............................................................................................................................ 113
Table 114: Trend for Aboriginal status for women who gave birth in WA, 1980-2012 ................................ 114
Table 115: Trend for place of birth for women who gave birth in WA, 1980-2012 ...................................... 115
Table 116: Trend for smoking tobacco during pregnancy in women who gave birth in WA, 19992012.............................................................................................................................................. 116
Table 117: Trend for number of previous infants for women who gave birth in WA, 1980-2012 ................ 117
Table 118: Trend for onset of labour for women who gave birth in WA, 1986-2012 ................................... 118
Table 119: Trend for method of birth for women who gave birth in WA, 1980-2012 .................................. 119
Table 120: Trend for gender of infants born in WA, 1980-2012 .................................................................. 120
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
List of Figures
Figure 1: Age of women who gave birth in WA, 1980-2012 ............................................................................ 7
Figure 2: Place of birth of metropolitan women who gave birth in WA, 2012 ................................................ 10
Figure 3: Trend of use of public and private hospitals by women who gave birth in WA, 1980-2012 .......... 13
Figure 4: Proportion of women smoking tobacco in first 20 weeks of pregnancy in WA, 2012 .................... 15
Figure 5: Proportion of women smoking tobacco after 20 weeks gestation in WA, 2012 ............................. 15
Figure 6: Trend in smoking tobacco during pregnancy of women who gave birth in WA, 1998-2012 .......... 16
Figure 7: Body mass index and age of women who gave birth in WA, 2012 ................................................ 20
Figure 8: Trend of number of previous infants of women who gave birth in WA, 1980-2012 ....................... 22
Figure 9: Onset of labour for women who gave birth in WA, 1986-2012 ...................................................... 29
Figure 10: Trend for method of birth for women who gave birth in WA, 1980-2012 ..................................... 42
Figure 11: Onset of labour by hours of labour for women who gave birth vaginally in WA, 2012 ................. 45
Figure 12: Trend for primary postpartum haemorrhage for women who gave birth in WA, 1986-2012 ........ 48
Figure 13: Trend for perineal status for women who gave birth vaginally in WA, 1993-2012 ....................... 51
Figure 14: Maternal age distribution by Aboriginal status for women who gave birth in WA, 2012 .............. 53
Figure 15: Maternal age-specific birth rates by Aboriginal status for women who gave birth in WA,
2012................................................................................................................................................ 55
Figure 16: Trend in maternal age-specific birth rates by Aboriginal status for women who gave birth
in WA, 1983-2012........................................................................................................................... 55
Figure 17: Number of previous infants and Aboriginal status of women who gave birth in WA, 2012.......... 59
Figure 18: Trends for number and crude birth rate for infants born alive in WA, 1980-2012 ........................ 82
Figure 19: Trends for gender of infants born in WA, 1980-2012 ................................................................... 83
Figure 20: Birthweight centiles for singleton male infants born alive in WA, 2012 ........................................ 86
Figure 21: Birthweight centiles for singleton female infants born alive in WA, 2012 ..................................... 87
Figure 22: Trends for place of birth of infants born alive at 23 to 31 weeks gestation in WA, 19862012................................................................................................................................................ 89
Figure 23: Trends for infants discharged Home within one day of birth in WA, 1980-2012 ........................ 103
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Executive summary
This is the thirtieth annual report on births in Western Australia (WA) from the Midwives'
Notification System. All tables presented here are in aggregated form without
identification of individual women, midwives or doctors.
The report contains information on women who gave birth in WA in 2012, and their
infants. Pregnancies that resulted in the birth of an infant of at least 20 weeks gestation
or more than 400 grams in weight have been included. These criteria are in accordance
with definitions provided by the National Health Data Dictionary.
In January 2012, and again in July 2012, the data collection was expanded. This report
includes these new data.
Permission has been received from health services to publish data at a hospital level in
this report. These data were first presented for 2010 births and describe percentage
rates for induction of labour, caesarean section and spontaneous vaginal birth for
infants with a vertex presentation.
Maternal demographics
In 2012, there were 33,393 women who gave birth in Western Australia, and their
average age was 29.7 years (Table 1 and Section 2.1.1).
Teenaged women, 19 years or younger, represented 4.0 per cent of women who gave
birth, the lowest proportion since 1980.
The age-specific birth rate for teenaged women was the lowest since 1983 at 17.4 per
1000 (Table 113).
Women aged 35 years or older represented 20.5 per cent of all who gave birth in 2012.
A similar proportion occurred each year since 2005 (Table 2).
The age-specific birth rate for women aged 35 and older was 40.0 per 1000 women,
similar to the rate occurring since 2007 (Table 113).
The largest proportion of WA women (78.2 per cent) resided in the metropolitan health
regions. In country health regions, the largest proportion of women (6.5 per cent) lived
in the Southwest (Table 3).
Place of birth
The majority (98.4 per cent) of women gave birth in hospitals. Non-hospital births (1.6
per cent) included women who gave birth at a birth centre (1.0 per cent) and at home
(0.6 per cent) (Table 9).
Of women resident in metropolitan regions, 72.9 per cent gave birth in hospitals in their
own regions and 20.0 per cent gave birth in the tertiary hospital (Table 7).
In country regions, 74.9 per cent of women gave birth in their own region and 9.3 per
cent gave birth in the tertiary hospital (Table 8).
Tobacco smoking during pregnancy
The proportion of women who reported smoking tobacco during pregnancy was 11.6
per cent. Among teenaged women the smoking proportion was 32.3 per cent (Table
11).
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Western Australia’s Mothers and Babies, 2012, 30th Annual Report
By country of birth, the highest proportions of women who reported smoking tobacco
were born in New Zealand (23.0 per cent) and Australia (15.0 per cent) (Table 12).
Pregnancy Profile
Women who gave birth for the first time represented 42.9 per cent of all women who
gave birth (Table 15). Their average age was 28.0 years.
Among women who were aged 35 years or more, 26.1 per cent had their first baby
(Table 15).
For women who had a BMI able to be calculated, 23.1 per cent were obese and 7.3 per
cent were underweight (Table 14).
Antenatal care in the first trimester of pregnancy occurred for 55.4 per cent of women. A
further 36.4 per cent had some antenatal care before birth. The remaining women did
not attend antenatal care (1.1 per cent) or attendance was not able to be determined
(7.0 per cent) (Table 16).
The proportion of women who attended more than five antenatal care visits was 69.2
per cent (Table 18).
Some women had pregnancies affected by one or more pre-existing medical conditions
(40.8 per cent). The most common condition was asthma (10.1 per cent). For women
who were obese in pregnancy, the proportion with asthma was 13.3 per cent (Table 19,
Table 20).
Some women had pregnancies affected by one or more complications of pregnancy
(33.1 per cent). The most common condition was gestational diabetes (7.0 per cent).
For women who were obese in pregnancy, the proportion with gestational diabetes was
11.5 per cent (Table 21, Table 22).
Labour and Birth
Spontaneous onset of labour occurred for 50.1 per cent of pregnant women and 29.1
per cent had labour induced. The remaining women (20.8 per cent) did not experience
labour prior to birth by caesarean section (Table 24).
Of women who had spontaneous onset of labour, 36.8 per cent had their labour
augmented (Section 2.3.2).
There was wide variation in the rate of Induction of labour across maternity sites. The
range was from 16.9 to 41.3 per cent (Table 30).
Epidural and/or spinal analgesia was used by 48.7 per cent of women during labour
(Table 31).
For women with a vertex presentation of first or only fetus, a spontaneous vaginal birth
occurred for 52.1 per cent. Within individual maternity sites, this proportion ranged
between 29.2 and 68.7 per cent (Table 38).
The caesarean section rate in 2012 was 34.6 per cent (11,541 women). There was wide
variation in the proportion for caesarean section across maternity sites. The range was
from 20.0 to 57.0 per cent (Table 41).
Complications of labour and birth, including reasons for caesarean section, were
reported for 62.2 per cent of women. The most common complications reported were
xii
Western Australia’s Mothers and Babies, 2012, 30th Annual Report
primary postpartum haemorrhage (19.3 per cent), previous caesarean section (17.1 per
cent), and suspected fetal compromise (10.2 per cent) (Table 43).
The rate of primary postpartum haemorrhage escalated in the past nine years from 8.2
to 19.3 per cent of women (Figure 12).
Complications of labour and birth were reported for 71.4 per cent of obese women.
These women had higher proportions of primary postpartum haemorrhage (26.9 per
cent), previous caesarean section (23.2 per cent) and suspected fetal compromise (11.1
per cent) than did all women (Table 44).
Aboriginal Mothers
Aboriginal women represented 4.9 per cent of those who gave birth in WA (Table 1).
They had a higher age specific birth rate (89.2 per 1000) than non-Aboriginal women
(64.3 per 1000) (Table 51).
The age specific birth rate for Aboriginal teenagers (86.8 per 1000) was higher than for
all Aboriginal women and was more than six times the rate for non-Aboriginal teenage
mothers (13.5 per 1000) (Table 51).
The highest proportion of Aboriginal women (64.1 per cent) lived in rural WA (Table 52).
More than half (52.0 per cent) of the Aboriginal women gave birth in public hospitals in
rural regions and 26.1 per cent gave birth in the tertiary hospital (Table 66).
Aboriginal women were half as likely (RR 0.6) to attend antenatal care within first
trimester and twice as likely (RR 2.2) to never attend antenatal care than non-Aboriginal
women (Table 53).
Aboriginal women with a history of stillbirth or children who died were more than twice
the proportion of non-Aboriginal women with this history (Table 57).
Almost half of the Aboriginal women reported smoking tobacco during pregnancy (48.2
per cent) (Table 58).
The proportion of Aboriginal women who lived in Perth and reported smoking tobacco
(47.6 per cent) was similar to those living in country regions (48.5 per cent) (Table 59).
More Aboriginal women had complications of pregnancy (39.6 per cent) than did nonAboriginal women (32.7 per cent). The proportion of Aboriginal women with gestational
diabetes (4.8 per cent) was slightly lower than for non-Aboriginal women (5.7 per cent)
(Table 62). However, a higher proportion of Aboriginal women had pre-existing diabetes
(2.3 per cent) than non-Aboriginal woman (0.7 per cent) (Table 63).
Following vaginal birth, Aboriginal women had a higher proportion of intact perineum
(63.3 per cent, 34.3 per cent respectively) and less than half the proportion of
episiotomy (8.3 percent, 21.4 percent respectively) than non-Aboriginal women, (Table
69).
xiii
Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Aboriginal infants
Of infants born to Aboriginal women, 1.7 per cent were stillborn compared to 0.6 per
cent of those born to non-Aboriginal women. The proportion of stillbirths that occurred
before onset of labour were higher in infants of Aboriginal women, 75.0 per cent and
56.9 percent respectively (Table 70).
The proportion of infants born to Aboriginal women who had low birthweight was 15.7
per cent compared with 6.2 per cent for infants of non-Aboriginal mothers (Table 74).
Since 2001, the RR for an infant of an Aboriginal mother having a low birthweight
compared to an infant of other mothers has fluctuated minimally and was 2.5 times the
risk for infants of non-Aboriginal women in 2012 (Table 76).
In addition to maternal Aboriginal status, this status was reported for infants born in
2012. An additional 190 infants were identified as Aboriginal or Torres Strait Islander
when their mother was not reported as of Aboriginal or Torres Strait Islander descent.
All Infants
In 2012, there were 33,862 infants born in Western Australia. Of these, 99.3 per cent
were born alive and 237 were stillborn (Table 80).
There was an increase in the number of infants born in WA since 2011 of 1,671 (5.2 per
cent) and the crude birth rate increased from 13.6 to 13.8 per 1000 total population over
the same period (Table 80).
There were 32,926 singleton infants born, representing 97.2 per cent of total infants
born. Of the 2.8 per cent of infants born in multiple births, there were 465 sets of twins
and 2 sets of triplets (Table 81).There were no births of higher order than triplet
reported.
The proportion of births that were preterm was 8.9 per cent.
Of all preterm infants, 93.0 per cent were born alive.
The majority (73.9 per cent) of stillborn preterm infants were born before 28 weeks
gestation (Table 83).
Of preterm liveborn infants, 89.7 per cent of those less than 32 weeks gestation were
born in the tertiary hospital (Table 87).
An Apgar score between 8 and 10 at one minute of age was reported for 85.3 per cent
of liveborn infants. An Apgar score between 8 and 10 at five minutes of age was
recorded for 96.7 per cent liveborn infants (Table 94 and Table 95).
For liveborn infants, 21.1 per cent received some form of resuscitation at birth (Table
96).
Of liveborn infants, 11.4 per cent were admitted to a Special Care Nursery at the birth
site for at least one day. Length of stay in Special Care Nursery exceeded 7 days for
27.1 per cent of these infants (Table 99).
Since 1980, the proportion of infants discharged home within one day of birth increased,
particularly in the recent five years from 2006 (9.5 per cent) to the highest ever
proportion of 17.6 per cent in 2012 (Figure 23).
xiv
Western Australia’s Mothers and Babies, 2012, 30th Annual Report
Perinatal Mortality
Among infants born in 2012 there were 237 fetal deaths and 48 neonatal deaths, a
perinatal mortality rate of 8.4 per 1000 total births (Table 104).
The perinatal mortality rate for infants of Aboriginal mothers was 21.1 per 1000 infants
born compared to 7.8 per 1000 infants of non-Aboriginal mothers (Table 104).
The perinatal mortality rate for infants of multiple births (27.8 per 1000 infants born) was
almost four times the rate for singleton infants (7.9 per 1000) (Table 109).
Cause of death for most stillborn infants was determined to be either extremely low
birthweight (43.0 per cent) or lethal birth defects (30.0 per cent) (Table 112).
Cause of death for most infants that died in the neonatal period was determined to be
either extremely low birthweight (41.7 per cent) or lethal birth defects (29.2 per cent)
(Table 112).
xv
Western Australia’s Mothers and Babies 2012, 30th Annual Report
1. Introduction
This is the thirtieth annual report on perinatal statistics in Western Australia (WA) from
the Midwives' Notification System (MNS).
The report contains information on women who gave birth in WA in 2012 and their
infants. Pregnancies that resulted in an infant at or greater than 20 weeks gestation or
more than 400 grams in weight have been included. These criteria are in accordance
with national reporting methods (AIHW 2009).
The report presents an overview of data on births for 2012 in terms of maternal
demography, procedures and infant outcomes. It also describes trends over the
collection period from 1980 to 2012 (where available). Information on women resident in
this State who gave birth outside WA is not included in this report.
To ensure complete ascertainment of births and perinatal deaths within WA, information
is collated from the WA MNS, the WA Hospital Morbidity System and the WA Registry
of Births, Deaths and Marriages. These data are maintained separately as state-wide
data collections.
This report includes some hospital level data with the permission of the Chief Executive
Officers of maternity services in Western Australia. The WA Country Health Service
data is presented in regions in these tables to more appropriately reflect the service
model provided in those regions.
Aboriginal women, their pregnancies, births and infants are described in a dedicated
section of this report.
1.1. Changes to report format and content
Changes were introduced to notification of birth data required of midwives. Three
changes commenced for births from 1st January 2012 and a fourth, “total number of
antenatal care visits” commenced for births from 1st July 2012. These additional data
have been used in this report to describe births in 2012. The changes were:




addition of “maternal weight (kg) at booking” as value;
addition of “total number of previous caesarean sections”;
addition of “total number of antenatal care visits” (in this pregnancy); and
addition of “aboriginal status of infant”.
Trend data from previous years has been updated with current data from the MNS
Collection and population data.
1.2. Legal status of perinatal statistics in Western Australia
Western Australia’s statutory reporting requirements are outlined in the Health Act 1911,
Section 355(1): “It shall be the duty of every midwife to furnish to the Executive Director,
Public Health and to the medical officer of health of the district in which she practises a
report in writing in the manner and at the time and in the form prescribed of every case
attended by her, whether of living, premature or full-term birth, or stillbirth, or abortion.”
The birth notification report should be submitted within 48 hours of the birth. This
enables the Community Child Health Nurse to monitor the health and welfare of the
mother and her infant.
A more comprehensive Notification of Case Attended (NOCA) (Form 2, Appendix C)
form is also to be submitted as required by the Health (Notifications by Midwives)
Regulations 1994. The submission of data should happen after the infant has been
1
Western Australia’s Mothers and Babies 2012, 30th Annual Report
discharged from hospital, or in the case of home birth, when the midwife is satisfied the
birth event has been completed.
The NOCA form can be updated without amendments to the Act. The last update to
include new variables and values was in 2012.
A midwife who enters into private practice must notify the Executive Director of Public
Health of this intention. Initial contact should be made to the Principal Midwifery Adviser
to the Chief Nurse and Midwifery Officer to formalise the process. The Midwifery
Adviser to the Chief Nursing Officer is now the delegate for the Executive Director of
Public Health for receiving notice from midwives to undertake private practice.
1.3. Midwives’ Notification System
The MNS is an Oracle database storing birth data since 1980. Data are submitted
electronically from a number of feeder systems or manually in paper forms. The main
electronic feeder systems providing birth data in 2012 were Stork, the Midwives’ Data
Entry Package (MDEP), the IBA system from the Ramsay Group hospitals and the
Midwives System from the SJOG Group. Stork is managed by the Department of
Health’s Health Information Network and the MDEP is maintained by the Maternal and
Child Health Unit. By 1st October 2012, all rural public maternity services provided 2012
data via Stork having progressed from use of one of the three systems, Stork, MDEP or
paper form.
1.4. Aboriginal status
Within Western Australia, the term Aboriginal is used in preference to Aboriginal and
Torres Strait Islander, in recognition that Aboriginal people are the original inhabitants of
Western Australia. No disrespect is intended to our Torres Strait Islander colleagues
and community.
Reporting Aboriginal status for women included in this report relied on multi-step
processes in place at health services. Usually, women completed a "Patient
Registration" health record form which included a requirement to respond to a question
about whether or not they are of Aboriginal or Torres Strait Islander descent. This form
is usually completed at every presentation to a health service with most women
expected to confirm the content multiple times during a pregnancy and birth admission.
When notifying a birth to the MNS, the midwife would have referred to this health record
form to complete the ethnicity data item. The relationship between the midwife and the
woman could have provided knowledge and opportunity to report a different ethnicity to
MNS than that recorded on the health record form.
A WA Department of Health Audit conducted in 2001 found that Aboriginal status was
under ascertained in WA hospitals with 85.8 per cent of Aboriginal people found to be
accurately reported in the hospital morbidity data. There was a range across health
regions of 78.3 to 93.5 per cent. A recommendation of the audit was for a correction
factor to be used when reporting health data to overcome under-ascertainment of
Aboriginal status (Young, M 2001). This Mothers and Babies report has not employed
the correction factor, nor have previous reports in this series.
A Commonwealth report of “quality of Indigenous identification in records of
hospitalisations in public hospitals in Australia” found that weighted completeness (and
confidence intervals) of these data for WA was 91 per cent (85-95 per cent). The report
recommended that these data should be used in any analyses of Indigneous
hospitalisation rates (AIHW 2013).
A validation of MNS data was last conducted in 2007 on data for the calendar year
2005. A review of the medical records for 525 (2%) randomly selected midwives’ birth
2
Western Australia’s Mothers and Babies 2012, 30th Annual Report
reports received to the MNS was conducted where data received was compared to the
physical medical record. The MNS data field "Ethnicity" includes reporting of
Aboriginal/TSI as one of a number of other ethnicities for the mother. 5.9% of birth
records were found to have a different ethnicity to that recorded in the medical record
(Downey, F 2007). Considering that the Young (2001) audit found that the Aboriginal
status recorded in the health medical record was incorrect in a proportion of records, it
is unknown whether the smaller difference found in the validation of Aboriginal status in
birth data in MNS was due to improved ascertainment as a consequence of the Young
audit. Validation of MNS data is due to be repeated and the design of the project will
include accuracy of ascertainment of maternal Aboriginal status and infant Aboriginal
status for births occurring from Jan 2012.
1.5. Presentation of data in report
All data presented here are in statistical form with values less than 5 suppressed and
suppression indicated with ***. There is no identification of individual patients, midwives
or doctors. Some data identifies hospitals when permitted. Readers requiring
suppressed values can request these data directly from the Maternal and Child Health
Unit.
3
Western Australia’s Mothers and Babies 2012, 30th Annual Report
1.6. Data provision model for Midwives’ Notification System - 2012
SYSTEM
FEEDERS
OUTCOMES
WA Birth Data
Stork 1
Data Entry Package
2
Annual Perinatal
Report
Oracle
Database
Ramsay Group IBA 3
(Since 1980)
Data Provisions:
NPESU, Planning,
Research,
Parliament, Media
and Ad-hoc requests
SJOG Group Sys 4
Paper 5
Birth
Notification
Community Child
Health Service
(Within 48hrs)
1.7. Data Sources for the 2012 birth data
1
Stork
Armadale Kelmscott Memorial Hospital, Bentley Health Service,
Bridgetown Hospital, Bunbury Regional Hospital, Busselton Hospital,
Collie Hospital, Community Midwife Program, Kaleeya Hospital, King
Edward Memorial Hospital, Margaret River Hospital, Osborne Park
Hospital, Rockingham General Hospital, Swan District Hospital, and
Warren Hospital.
1/2
Use of Midwives Data Entry
Package or Paper Forms replaced
by Stork during 2012
Albany Hospital, Broome Hospital, Carnarvon Hospital, Derby Hospital
Esperance Hospital, Geraldton Hospital, Hedland Health Campus,
Kalgoorlie Hospital, Katanning Hospital, Kununnurra Hospital, Narrogin
Hospital, Northam Hospital, and Nickol Bay Hospital
2
Midwives Data Entry Package
Mercy Hospital, Peel Health Campus
3
Ramsay Group IBA
Attadale Hospital, Glengarry Hospital, Joondalup Health Campus
4
SJOG Group Perinatal Dbase
St John of God – Murdoch, St John of God – Subiaco, St John of God –
Geraldton, St John of God - Bunbury .
5
Paper Forms
Private Practice Midwives and others
4
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2. Mothers
In 2012, there were 33,393 women who gave birth in WA (Table 1). This was an
increase of 1,659 women (5.2 per cent) from 2011 and was the highest annual number
of women giving birth since 1974, since when data are available. Of women who gave
birth, 4.9 per cent were Aboriginal, the remaining including those reported as
Caucasian, Asian, African, Indian, Maori or other (Table 1).
Table 1: Aboriginal status of women who gave birth in WA, 2012
Aboriginal Status
Aboriginal
non-Aboriginal
Total
Number
1630
31763
33393
Percentage
4.9
95.1
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
5
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.1. Maternal demographics
2.1.1.
Maternal age
The age of mothers that gave birth in 2012, ranged from 13 to 50 years with a mean of
29.7 years and a median and mode of 30 years.
Over the past three decades, the proportion of teenage women giving birth declined
from 8.2 per cent in 1980 to 4.0 per cent in 2012. The proportion of women aged 20 to
34 years also decreased from 87.4 per cent in 1983 to 73.4 per cent in 2007. This
proportion has since increased to 75.5 per cent by 2012. In the same period, the
proportion of women aged 35 years or older increased from 4.7 per cent in 1980 and
was 20.5 per cent in 2012 (Table 2, Figure 1).
Table 2: Age of women who gave birth in WA, 1980-2012
Year of Birth
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
≤19
No.
%
1698
8.2
1770
8.1
1643
7.4
1577
6.9
1542
6.8
1455
6.3
1535
6.5
1494
6.3
1635
6.6
1586
6.3
1662
6.5
1639
6.6
1574
6.3
1496
6.0
1592
6.3
1521
6.1
1521
6.0
1446
5.8
1520
6.0
1509
5.9
1479
6.0
1423
5.8
1438
5.9
1338
5.5
1390
5.5
1484
5.6
1514
5.4
1512
5.1
1534
5.1
1468
4.8
1351
4.4
1367
4.3
1342
4.0
Maternal Age
20-34
No.
%
17928 87.1
19110 86.9
19271 87.0
19955 87.4
19807 87.2
20062 86.9
20344 86.2
20597 86.2
21084 85.0
21372 85.0
21617 84.1
20599 83.5
20756 83.1
20670 82.8
20515 81.8
20391 81.3
20298 80.6
19898 80.0
19926 78.8
19977 78.7
19366 78.0
19007 77.6
18874 77.4
18557 76.4
19092 76.0
19849 74.8
20960 74.2
21900 73.9
22188 73.4
22880 74.4
22998 74.6
23727 74.8
25206 75.5
≥ 35
No.
969
1100
1238
1294
1354
1559
1724
1804
2083
2199
2423
2440
2639
2807
2964
3176
3374
3524
3846
3891
3972
4065
4084
4380
4630
5192
5780
6217
6509
6400
6486
6640
6845
%
4.7
5.0
5.6
5.7
6.0
6.8
7.3
7.5
8.4
8.7
9.4
9.9
10.6
11.2
11.8
12.7
13.4
14.2
15.2
15.3
16.0
16.6
16.7
18.0
18.4
19.6
20.5
21.0
21.5
20.8
21.0
20.9
20.5
Total
No.
20595
21980
22152
22826
22703
23076
23603
23895
24802
25157
25702
24678
24969
24973
25071
25088
25193
24868
25292
25377
24817
24495
24396
24275
25112
26525
28254
29629
30231
30748
30835
31734
33393
Extracted from Midwives’ Notification System on 20 June 2014.
6
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Figure 1: Age of women who gave birth in WA, 1980-2012
Proportion of all women giving birth (%)
100
90
80
70
60
50
40
30
20
10
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
0
Year
<=19 yrs
20-34 yrs
>=35 yrs
2.1.2.
Place of Residence
The state of Western Australia is divided geographically into three health areas and nine
health regions. The metropolitan areas are also defined as regions, while the country
area has seven regions1.
The majority of women who gave birth in WA in 2012 (78.2 per cent) resided in the
metropolitan health regions. Of the country health regions, the Southwest had the
largest proportion (6.5 per cent) (Table 3).
Table 3: Place of residence of women who gave birth in WA, 2012
Total
Region of Residence by postcode
Metropolitan Health Regions
North
South
No.
26115
13323
12792
Country Health Regions
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Not resident in a WA health region
Total
%
78.2
39.9
38.3
7232
959
711
681
891
875
2164
951
21.7
2.9
2.1
2.0
2.7
2.6
6.5
2.8
46
33393
0.1
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
1
See Glossary for description of Health Area and Health Region
7
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.1.3.
Country of birth
The country of birth was recorded in the Hospital Morbidity Data Collection (HMDC) for
97.9 per cent of the 33,393 women who gave birth in WA in 2012 (Table 4).
Of these women, more than one-third (35.8 per cent) were born in countries other than
Australia. Mothers born in the United Kingdom accounted for a relatively high proportion
of all mothers in WA (7.2 per cent). New Zealand-born mothers constituted 4.4 per cent
of all women giving birth. Mothers born in Asian countries represented the highest
proportion (13.7 per cent) of women with non-Australian birthplaces (Table 4).
Table 4: Country of birth of women who gave birth in WA, 2012
≤ 19
Country of birth
Oceania
Australia
New Zealand
Maternal age
20–34
No.
%
No.
%
1104
80
83.4
6.0
15938
1092
64.6
4.4
Europe
United Kingdom and Ireland
Other Europe
39
***
2.9
***
1611
609
Asia
Vietnam
Malaysia
Other SE Asia
Other Asia
***
12
8
***
0.9
0.6
Africa
South Africa and Zimbabwe
Other Africa and Middle East
18
53
Americas
North America
South and Central America
Other Pacific
Total
≥ 35
No.
Total
%
No.
%
3933
261
59.8
3.7
20975
1433
64.2
4.4
6.5
2.5
720
241-246
11.2
3.4
2370
855
7.2
2.6
286
316
1001
1899
1.2
1.3
4.1
7.7
90-95
124
341
402
1.4
1.8
5.1
6.0
381
440
1354
2309
1.2
1.3
4.1
7.1
1.4
4.0
519
989
2.1
4.0
204
223
3.0
3.3
741
1265
2.3
3.9
***
***
***
***
197
128
0.8
0.5
69-74
60-65
1.1
0.9
269
193
0.8
0.6
***
1324
***
100.0
78
24663
0.3
100.0
27-32
6708
0.5
100.0
110
32695
0.3
100.0
Extracted from Midwives’ Notification system 20 June 2014 with country of birth data provided from the Hospital Morbidity Data
System.
There were 698 cases (2.1 per cent) where the mother’s county of birth was unable to be ascertained.
Values <5 are suppressed and indicated with ***, values in the same row are provided as a range to prevent calculation of the
suppressed value.
8
Western Australia’s Mothers and Babies 2012, 30th Annual Report
In the 5-year period 2008 to 2012, 67.8 per cent of all mothers were born in Australia
(Table 5). Over the same period, the proportion of Australian born women giving birth
declined.
Table 5: Trend of country of birth of women who gave birth in WA, 2008-2012
2008
No.
%
%
2010
%
%
2011
No.
%
2012
No.
%
Total
%
20997
1155
70.0
3.9
20552
1156
68.3
3.8
20560
1212
66.1
3.9
20975
1433
64.2
4.4
67.8
3.9
7.5
2.5
2168
752
7.2
2.5
2173
753
7.2
2.5
2238
826
7.2
2.7
2370
855
7.2
2.6
7.3
2.6
311
295
914
965
1.1
1.0
3.1
3.3
298
316
991
1229
1.0
1.1
3.3
4.1
268
334
1045
1603
0.9
1.1
3.5
5.3
278
408
1227
1924
0.9
1.3
3.9
6.2
381
440
1354
2309
1.2
1.3
4.1
7.1
1.0
1.2
3.6
5.2
598
2.0
640
2.1
653
2.2
689
2.2
741
2.3
2.2
915
3.1
977
3.3
1099
3.7
1203
3.9
1265
3.9
3.6
212
0.7
231
0.8
211
0.7
257
0.8
269
0.8
0.8
168
0.6
177
0.6
173
0.6
204
0.7
193
0.6
0.6
Country
groups
Oceania
Australia
New Zealand
20856
1063
71.1
3.6
Europe
UK & Ireland
Other Europe
2210
739
Asia
Vietnam
Malaysia
Other SE Asia
Other Asia
Africa
South Africa &
Zimbabwe
Other Africa &
Middle East
Americas
North America
South &
Central
America
Other Pacific
Total
2009
No.
83
0.3
64
0.2
89
0.3
97
0.3
110
0.3
0.3
29329
100.0
29995
100.0
30109
100.0
31123
100.0
32695
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
There were 3,690 cases (902, 753, 726, 611 and 698 by year) where the mother’s county of birth was unable to be ascertained.
2.1.4.
Marital status
At the time they gave birth, 84.1 per cent of women in WA were reported as being in a
married or defacto relationship. Women who were never married (single) represented
13.9 per cent and the remaining women (2.0 per cent) were either separated, divorced,
widowed or had no status reported (Table 6).
Table 6: Marital status and plurality of women who gave birth in WA, 2012
Marital status
Single
Married/Defacto
1
Other
Total
Plurality
Single
Multiple
No.
%
No.
%
4600
14.0
52
11.1
27669
84.0
407
87.2
657
2.0
8
1.7
32926 100.0
467 100.0
Total
No.
4652
28076
665
33393
%
13.9
84.1
2.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
1
“Other” marital status included separated, divorced, widowed and unknown.
9
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.1.5.
Place of birth
Among women resident in the metropolitan health areas, the majority gave birth in
hospitals within their own health area (72.9 per cent) or at the tertiary maternity service
(20.0 per cent) (Table 7 and Figure 2).
Table 7: Place of birth of metropolitan women who gave birth in WA, 2012
Health area of
residence
Own area
North Metro
South Metro
Total
10059
8973
19032
North Metro
South Metro
Total
75.5
70.1
72.9
North Metro
South Metro
Total
52.9
47.1
100.0
Health area of birth site
Other
metro area
Tertiary
Number
336
2816
1292
2420
1628
5236
Row Percentage
2.5
21.1
10.1
18.9
6.2
20.0
Column Percentage
20.6
53.8
79.4
46.2
100.0
100.0
Total
Country
area
Homebirths
15
28
43
100
81
181
13326
12794
26120
0.1
0.2
0.2
0.8
0.6
0.7
100.0
100.0
100.0
34.9
65.1
100.0
55.2
44.8
100.0
51.0
49.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Homebirths are allocated to the health area of the woman’s residence.
Proportion of birthing women living in Health Area
Figure 2: Place of birth of metropolitan women who gave birth in WA, 2012
80
75.5
70.1
70
60
50
40
30
21.1
18.9
20
10.1
10
2.5
0
Tertiary
North
South
Health area of birth site
North Metro
South Metro
Women living in North Metro area also gave birth in the country and at home (0.9 per cent)
Women living in South Metro area also gave birth in the country and at home (0.8 per cent).
10
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Among women who were resident in a country area, 76.3 per cent gave birth in their
own region. A further 1.9 per cent gave birth in another country region. A small
proportion of country women had homebirths (0.5 per cent).
Of women living in the country, 9.0 per cent gave birth at the tertiary maternity service
and 12.3 per cent birthed at another metropolitan health service (Table 8).
Table 8: Place of birth of country women who gave birth in WA, 2012
Birth hospital health region
Other
North
South
WACHS
Tertiary
Metro
Metro
Number
6-11
68
27
8
39
80
28
14-19
11
68
13
3-8
16
83
48
6-11
27-32
82
101
65
7
106
34
22
31-36
186
402
142
Health region
of residence
Own
Region
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
847
546
581
734
853
1976
186
5723
142
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
88.1
76.7
85.3
82.3
75.3
91.3
19.5
76.3
0.7
5.5
1.6
1.8
2.6
0.3
3.5
1.9
673
653
Row Percentage
7.1
2.8
11.2
3.9
10.0
1.9
9.3
5.4
7.2
8.9
4.9
1.6
19.5
42.2
9.0
8.7
Home
Total
***
***
***
***
***
20
***
961
712
681
892
1133
2165
952
269
36
7496
0.7
2.4
0.7
1.1
5.7
1.0
14.9
3.6
0.4
0.3
0.4
0.1
0.3
0.9
0.3
0.5
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Homebirths are allocated to a health area of birth site by assuming the birth took place in woman’s own home.
Values <5 are suppressed and indicated with ***, values in the same row are provided as a range to prevent calculation of the
suppressed value.
11
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.1.6.
Place of birth event
As well as the actual place of birth of an infant, midwives reported the Intended Place of
Birth at the time of onset of labour.
Eighty-five women of 33,393 (0.3 per cent) who gave birth in WA in 2012 had no
intended place of birth at onset of labour recorded. Of the remaining women, 97.6 per
cent intended to give birth in a hospital, 1.6 per cent in a birth centre and 0.8 per cent at
home.
Of the 527 women who intended to give birth in a birth centre, 322 (61.1 per cent)
achieved this goal. For women who intended to have birth at home, 98.6 per cent
achieved a birth at home.
The tertiary maternity service reported births for 209 women who did not intend to give
birth in a hospital. These comprised 3.1 per cent (birth centre) and 0.6 per cent
(homebirth) of the total women giving birth at the tertiary hospital (Table 9).
Table 9: Place of birth and intended place of birth of women who gave birth in
WA, 2012
Intended place of birth
Birth Centre
Home
Number
Tertiary hospital
5370
175
34
Public hospital1
13478
6
20
Private hospital2
13672
21
Birth centre
***
319-324
Home
***
203-208
Total
32519-32522
526-531
257-262
Percentage by actual place of birth
Tertiary hospital
96.3
3.1
0.6
Public hospital
99.8
0.0
0.1
Private hospital
99.8
0.2
Birth centre
0.6
99.4
Home
1.4
98.6
Total
97.6
1.6
0.8
Percentage by intended place of birth at onset of labour
Tertiary hospital
16.5
33.2
13.1
Public hospital
41.4
1.1
7.7
Private hospital
42.0
4.0
Birth centre
0.0
61.1
Home
0.6
79.2
Total
100.0
100.0
100.0
Actual place of birth
Hospital
Total
5579
13504
13693
324
208
33308
100.0
100.0
100.0
100.0
100.0
100.0
16.7
40.5
41.1
1.0
0.6
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excluded are 85 cases did not have one of the three intended places of birth specified.
Included are 118 cases that were reported as Born Before Arrival to reporting site.
Birth Centre births include those at the freestanding birth centre at Kalamunda Hospital.
Values <5 are suppressed and indicated with ***, values in the same row are provided as a range to prevent calculation of the
suppressed value.
1
2
Includes all maternity services located at public hospitals in Western Australia
Includes private and public admissions at private hospitals in Western Australia
12
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Trend data indicate that the proportion of births at private hospitals over the past 30
years increased and in 2012 equalled the proportion that occurred at public hospitals,
excluding the tertiary hospital. This increase mostly occurred in the period 1997–2001.
The proportion of births at the tertiary hospital remained relatively constant. In the most
recent 5-year period, this proportion was between 16.7 and 20.3 per cent of the women
giving birth (Figure 3, Table 115).
Figure 3: Trend of use of public and private hospitals by women who gave birth in
WA, 1980-2012
60.0
Proportion of women
50.0
40.0
30.0
20.0
10.0
0.0
1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012
Year
Tertiary
Public
Private
Women who gave birth while admitted publicly in private hospitals are reported here as occurring in private hospitals.
13
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Plurality of pregnancy influenced the place of birth. The metropolitan tertiary hospital
was the place of birth for 45.0 per cent of women with multiple pregnancy and 17.4 per
cent of those with a singleton pregnancy.
Private hospitals in metropolitan or country areas were the location for 35.8 per cent of
the multiple births. The remaining women with multiple pregnancies gave birth at
metropolitan public hospitals (11.8 per cent) or rural maternity services (6.9 per cent)
and a small number at other public country hospitals (Table 10).
Table 10: Place of birth and plurality of women who gave birth in WA, 2012
Plurality
Place of birth
Metropolitan
Tertiary hospital
Public hospital
Private hospital
Country
Regional hospital1
Private hospital
Other2
Homebirths
Grand Total
Single
No.
27105
5718
8694
12693
%
82.3
17.4
26.4
38.6
Multiple
No.
%
425
91.0
210
45.0
55
11.8
160
34.3
Total
No.
27530
5928
8749
12853
%
82.4
17.8
26.2
38.5
5605
3284
836-841
1485-1490
17.0
10.0
2.5
4.5
42
32
5-10
***
9.0
6.9
1.5
0.6
5647
3316
841
1490
16.9
9.9
2.5
4.5
216
32926
0.7
100.0
467
100.0
216
33393
0.6
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
128 cases that were reported as Born Before Arrival were included for reporting site‘s place of birth type.
Values <5 are suppressed and indicated with ***, values in the same row or column are provided as a range to prevent calculation
of the suppressed value.
2.1.7.
Smoking tobacco during pregnancy
Smoking tobacco during pregnancy is associated with low birth weight, premature birth,
and perinatal death.
From January 2010, the method for reporting tobacco smoking during pregnancy
changed from a Yes or No response to providing the average number of tobacco
cigarettes smoked each day before 20 weeks of pregnancy and after 20 weeks of
pregnancy.
When the two new data values self-reported for tobacco smoking were combined, they
were used to indicate if the woman smoked tobacco in pregnancy. These combined
data are presented below to enable comparison reporting with data published in
previous annual reports. Because of the change in method of reporting, changes in
rates between 2009 and 2010 should be interpreted with caution.
Data presented in Figure 4 and Figure 5 display the variation in self-reported rate of
tobacco smoking across health regions of maternal residence. Many country regions
had a higher proportion of women who reported smoking or occasionally smoking than
occurred in women living in the metropolitan regions. For WA, the proportion of women
who reported not smoking tobacco, increased after 20 weeks gestation by 1.5 per cent
(515 women). There was no change after 20 weeks gestation in the proportion of
women where smoking status was undetermined.
1
2
Country regional hospital – public hospital in regional centre.
Other Country hospital – public hospital in the country but not in a regional centre.
14
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Figure 4: Proportion of women smoking tobacco in first 20 weeks of pregnancy in
WA, 2012
45
Undetermined Cig Smoking
Proportion of Women living in Health Region
40
Occasional Smoking
35
1-10 Cigs/Day
11-20 Cigs/Day
30
>20 Cigs/Day
25
20
15
10
5
0
Region of Maternal Residence
Figure 5: Proportion of women smoking tobacco after 20 weeks gestation in WA,
2012
Proportion of Women living in Health Region
45
Undetermined Cig Smoking
40
Occasional Smoking
35
1-10 Cigs/Day
30
11-20 Cigs/Day
25
>20 Cigs/Day
20
15
10
5
0
Region of Maternal Residence
15
Western Australia’s Mothers and Babies 2012, 30th Annual Report
In 2012, 32.3 per cent of teenaged mothers reported smoking during pregnancy. As
maternal age increased the proportion of women who reported smoking tobacco
decreased to 8.2 per cent of women who were 40 years or older. Women aged 35 to 39
years had the lowest proportion reporting smoking tobacco (6.7 per cent). Overall, 11.6
per cent of women pregnant in WA were reported as smoking tobacco during pregnancy
(Table 36).
Table 11: Smoking and age of women who gave birth in WA, 2012
Age
<=15
16
17
18
19
≤19
20-24
25-29
30-34
35-39
>=40
Total
Smoking in pregnancy
Smoking
Non-smoking
No.
%
No.
%
12
30.0
28
70.0
33
31.1
73
68.9
85
33.5
169
66.5
137
36.0
244
64.0
166
29.6
395
70.4
433
32.3
909
67.7
1087
1075
788
375
105
3863
22.1
11.3
7.3
6.7
8.2
11.6
3825
8469
9962
5196
1169
29530
77.9
88.7
92.7
93.3
91.8
88.4
Total
No.
40
106
254
381
561
1342
%
100.0
100.0
100.0
100.0
100.0
100.0
4912
9544
10750
5571
1274
33393
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014,
62 women were aged 45 years or more.
The proportion of women reported as smoking tobacco during pregnancy declined from
22.6 per cent in 1999, when data was first collected in WA, to 11.6 per cent in 2012
(Figure 6 and Table 116).
Figure 6: Trend in smoking tobacco during pregnancy of women who gave birth
in WA, 1998-2012
Proportion of women
25
20
15
10
5
0
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
Year
The method of reporting tobacco smoking in pregnancy changed in 2010. The change in trend seen in 2010 in this graph should be
interpreted with caution.
16
Western Australia’s Mothers and Babies 2012, 30th Annual Report
In 2012, reporting smoking tobacco during pregnancy was more likely in mothers born
in New Zealand (22.9 per cent) and Australia (15.0 per cent) (Table 37). Mothers born in
Asian or African countries were least likely to report smoking tobacco during pregnancy.
Eight per cent of European born mothers were reported as smoking tobacco in
pregnancy.
Table 12: Smoking tobacco and country of birth of women who gave birth in WA,
2012
Smoking in pregnancy
Smoking
Non-smoking
No.
%
No.
%
Total
No.
%
3138
329
15.0
23.0
17837
1104
85.0
77.0
20975
1433
100.0
100.0
Europe
UK & Ireland
Other Europe
179
35
7.6
4.1
2191
820
92.4
95.9
2370
855
100.0
100.0
Asia
Vietnam
Malaysia
Other SE Asia
Other Asia
5
5
31
16
1.3
1.1
2.3
0.7
376
435
1323
2293
98.7
98.9
97.7
99.3
381
440
1354
2309
100.0
100.0
100.0
100.0
Africa
South Africa & Zimbabwe
Other Africa & Middle East
24
29
3.2
2.3
717
1236
96.8
97.7
741
1265
100.0
100.0
12
5
5
3813
4.5
4.5
2.6
11.7
257
105
188
28882
95.5
95.5
97.4
88.3
269
110
193
32695
100.0
100.0
100.0
100.0
Country of birth
Oceania
Australia
New Zealand
America
North America
Other Pacific
South & Central America
Total
Extracted from Midwives’ Notification System on 20 June 2014.
698 women excluded in table as their country of birth was not reported.
17
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.1.8.
Socio-economic status
Socio-economic status was assessed for residential area of all women who gave birth in
WA in 2012. A small number of women (302 or 0.9 per cent) had insufficient data to be
included.
The Index of Relative Socio-Economic Disadvantage (IRSD) from the Socio-Economic
Index for Areas (SEIFA) determined from the 2011 Australian Census data was used1.
The Index summarises different measures like low income, low education, and high
unemployment to obtain a ranking of each area’s disadvantage called the index value,
average index value and quantiles. Quantiles which divide the distribution of index
values into five equal parts are referred to as quintiles.
In the quintiles presented below in Table 13, “I” indicates women who gave birth while
living in areas within the 20 per cent most disadvantaged of IRSD values in WA in 2012.
“V” indicates women who gave birth while living within areas within the 20 per cent least
disadvantaged of IRSD in WA in 2012.
In women aged 19 years or less, most (57.2 per cent) have an IRSD value in the first
and second quintile, indicating most of these women live in areas that are
disadvantaged. In women aged 20 to 34 years that gave birth in 2012, the largest
proportion (25.2 per cent) was in the fourth quintile indicating residence in areas of less
disadvantage. For older women aged 35 years or more, the largest proportion (27.0 per
cent) were also in the fourth quintile.
When comparing contribution by age group in each quintile, women aged 35 years had
their highest proportion in the fifth quintile or least disadvantaged group for residential
area (28.5 per cent), while teenaged women had their highest proportion in the first
quintile or most disadvantaged group (7.8 per cent).
1
For more information on the Disadvantage Index from SEIFA go to
http://www.abs.gov.au/AUSSTATS/[email protected]sf/Lookup/2033.0.55.001Main+Features12012?OpenDocume
nt.
18
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 13: Socio-economic status and age of women who gave birth in WA, 2012
Disadvantage
1
I
II
III
IV
V
Total
I
II
III
IV
V
Total
I
II
III
IV
V
Total
Maternal age (years)
20–34
Number
478
4698
283
4414
302
5534
187
6284
80
4046
1330
24976
Percentage by Column
35.9
18.8
21.3
17.7
22.7
22.2
14.1
25.2
6.0
16.2
100.0
100.0
Percentage by Row
7.8
77.1
5.0
78.0
4.2
76.2
2.3
75.7
1.4
70.2
4.0
75.5
≤ 19
≥ 35
Total
919
964
1429
1832
1641
6785
6095
5661
7265
8303
5767
33091
13.5
14.2
21.1
27.0
24.2
100.0
18.4
17.1
22.0
25.1
17.4
100.0
15.1
17.0
19.7
22.1
28.5
20.5
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
IRSD values were determined from maternal address using the Statistical Area 2 value (SA2).
302 cases were excluded as there was no SA2 value able to be assigned.
2.2. Pregnancy profile
2.2.1.
Maternal Weight
The Australian Department of Health (DoHA 2009) reports that a healthy Body Mass
Index (BMI) is between 18.5 and 24.99. Further, a BMI that indicates the person is
overweight was divided into four categories, Pre-obese and Obese classes 1 to 3.
BMI Category
Underweight
Healthy weight
BMI
Less than 18.5
18.50 to 24.99
Risk of health consequences
Low - possibly increased risk of other clinical problems
Average
Overweight:
Pre-obese
Obese class 1
Obese class 2
Obese class 3
25.00 to 29.99
30.00 to 34.99
35.00 to 39.99
40 or more
Increased
Moderate
Severe
Very severe
Reporting of maternal weight commenced for births occurring from January 2012. Of the
women who gave birth in 2012, 92.6 per cent had weight reported. Both weight and
height were available to calculate a Body Mass Index (BMI) for 91.6 per cent of the
women who gave birth.
Of women who gave birth in 2012, the highest proportion (44.8 per cent) had a healthy
BMI. Almost a third of women (30.0 per cent) were Pre-obese (Table 14).
Obese women comprised 23.1 per cent of the women. A severe to very severe risk of
health consequences related to obesity was possible for 8.7 per cent of the women who
gave birth. A small proportion of women were reported as underweight (2.0 per cent).
More teenaged women were underweight (5.2 per cent) than women in other age
groups (2.0 and 1.4 per cent respectively).
19
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 14: Body mass index and age of women who gave birth WA, 2012
BMI Category
Underweight
Healthy weight
Pre-obese
Obese class 1
Obese class 2
Obese class 3
Total
Less than 18.5
18.5 to 24.99
25 to 29.99
30 to 34.99
35 to 39.99
40 or more
Total
Less than 18.5
18.5 to 24.99
25 to 29.99
30 to 34.99
35 to 39.99
40 or more
Total
Maternal age (years)
≤ 19
20–34
≥ 35
Number
64
472
85
607
10422
2685
336
6908
1925
147
3263
987
44
1353
360
23
703
195
1221
23121
6237
Percentage by Column
5.2
2.0
1.4
49.7
45.1
43.0
27.5
29.9
30.9
12.0
14.1
15.8
3.6
5.9
5.8
1.9
3.0
3.1
100.0
100.0
100.0
Percentage by Row
10.3
76.0
13.7
4.4
76.0
19.6
3.7
75.3
21.0
3.3
74.2
22.4
2.5
77.0
20.5
2.5
76.3
21.2
4.0
75.6
20.4
Total
621
13714
9169
4397
1757
921
30579
2.0
44.8
30.0
14.4
5.7
3.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
2,814 cases were excluded as there was either no weight or height available to calculate BMI.
The proportions excluded were 4.3, 74.1 and 21.6 per cent for age groups listed above.
Less than half of teenaged women were above a healthy BMI (45.0 per cent) compared
to more than half of women 35 years or older (55.6 percent) (Figure 7).
Figure 7: Body mass index and age of women who gave birth in WA, 2012
Maternal Age Group
≥ 35
Underweight
Healthy weight
20–34
Pre-obese
Obese class 1
Obese class 2
≤ 19
Obese class 3
0%
20%
40%
60%
80%
100%
Proportion of women with BMI calculated
20
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.2.2.
Parity
Data collected in WA, reported parity as number of infants born from previous
pregnancies rather than number of previous pregnancies resulting in birth.
As indicated in Table 15, 42.9 per cent of women who gave birth in 2012, gave birth to
their first infant.
Of these 14,312 women:
 8.0 per cent were teenagers (age of 19 or less years)
 79.5 per cent were aged 20 to 34 years
 13.5 per cent were aged 35 years or more
 Their mean maternal age was 28.0 years (range 13-50)
 Their median maternal age was 28 years, and
 Their mode or most commonly occurring maternal age was 30 years.
Of the 16,285 women who gave birth to their second or third infant in 2012:
 1.2 per cent were teenage women
 74.4 per cent were aged 20 to 34 years
 24.4 per cent were women aged 35 years or more
 Their mean maternal age was 30.7 years (range 16-48)
 Their median maternal age was 31 years, and
 Their mode or most commonly occurring maternal was 32 years.
Among the 6,845 women aged 35 years or more, 26.1 per cent gave birth to their first
baby in 2012.
Table 15: Previous infants and age of women who gave birth in WA, 2012
Number of
Previous
Infants
Maternal age
≤ 19
No.
Total
≥ 35
20–34
%
No.
%
No.
%
No.
%
Nil
% of Total
1141
8.0
85.0
11384
79.5
45.2
1787
12.5
26.1
14312
100.0
42.9
One or two
% of Total
201
1.2
15.0
12109
74.4
48.0
3975
24.4
58.1
16285
100.0
48.8
Three or four
% of Total
-
-
1449
74.4
5.7
817
24.4
11.9
2266
100.0
6.8
Five or more
% of Total
-
-
264
49.8
1.0
266
50.2
3.9
530
100.0
1.6
1342
4.0
100.0
25206
75.5
100.0
6845
20.5
100.0
33393
100.0
100.0
Total
% of Total
Extracted from Midwives’ Notification System on 20 June 2014.
21
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Trend data shows that the proportion of women who gave birth to their first infant
increased since 2002 from 40.6 per cent to 42.9 per cent in 2012. The proportion of
women who had their fourth and fifth infants declined from 8.4 per cent in 2002 to 6.8
per cent in 2012 (Figure 8).
Figure 8: Trend of number of previous infants of women who gave birth in WA,
1980-2012
55
45
40
35
30
25
20
15
10
5
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
0
1980
Proportion of all women giving birth (%)
50
Year
No previous babies
1-2 previous babies
3-4 previous babies
5 or more previous babies
22
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.2.3.
Pregnancy gestation at first antenatal care visit
In 2012, the largest proportion of women had their first antenatal care in the first
trimester of pregnancy (55.4 per cent). A small number of women received no antenatal
care (1.1 per cent).
Women who lived in the Southwest health region had the highest proportion (55.7 per
cent) that received antenatal care in the first trimester of all health regions. Women who
resided in the Goldfields region had the lowest proportion attending antenatal care in
first trimester (35.8 per cent) and the highest undetermined proportion (46.3 per cent).
The health region of residence with the lowest “not determined” rate was the North
Metropolitan at 1.2 per cent (Table 16).
Table 16: Gestation at first antenatal care visit of women who gave birth in WA,
2012
Health Region maternal
residence
1-12
North Metropolitan
South Metropolitan
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Outside WA
Total
7319
7365
343
358
335
480
396
1422
468
28
18514
North Metropolitan
South Metropolitan
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Outside WA
Total
54.9
57.6
35.8
50.4
49.2
53.9
45.3
65.7
49.2
60.9
55.4
Gestational Age Groups (weeks)
Did not
13–24
>24
Attend
Number
4519
3630
105
94
187
213
323
196
276
9
9552
1243
869
50
28-32
61-66
74
115
40-45
120-125
6
2619
Row Percentage
33.9
28.4
10.9
13.2
27.5
23.9
36.9
9.1
29.0
19.6
28.6
9.3
6.8
5.2
4.2
9.4
8.3
13.1
2.0
13.0
13.0
7.8
Not
Determ
Total
11
22
6
***
***
5
***
***
***
51
231
906
455
227
93
119
41
501
82
***
2657
13323
12792
959
711
681
891
875
2164
951
46
33393
0.1
0.2
0.6
0.3
0.3
0.6
0.0
0.1
2.2
0.2
1.7
7.1
47.4
31.9
13.7
13.4
4.7
23.2
8.6
4.3
8.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***.
23
Western Australia’s Mothers and Babies 2012, 30th Annual Report
For 2012, data collection improved with better ascertainment of gestational age at first
visit. There was a decrease from 24.4 per cent in 2010 to 7.0 percent in 2012 of women
with gestation at first antenatal care visit unable to be determined (Table 17).
Table 17: Trends for gestation at first antenatal care visit for women who gave
birth in WA, 2010-2012
Year
Gestational Age Groups (weeks)
Did not
13–24
>24
Attend
1-12
2010
2011
2012
12099
15291
18514
2010
2011
2012
39.2
48.2
55.4
Not
Determ
Total
Number
8109
9450
9552
2953
3206
2619
165
616
371
7517
3171
2337
30843
31734
33393
Row Percentage
26.3
29.8
28.6
9.6
10.1
7.8
0.5
1.9
1.1
24.4
10.0
7.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
This data first collected in 2010.
2.2.4.
Number of antenatal care visits during pregnancy
Reporting the number of antenatal care visits attended commenced for births occurring
from July 2012. Of women who gave birth in 2012, 58.2 per cent had a value reported.
The proportion of women who attended more than five antenatal care visits was 69.2
per cent, 40.9 per cent attended more than eight. A small proportion (0.4 per cent) had
zero visits attended. The majority of women who had homebirths had more than eight
visits (71.7 per cent). While in women who gave birth in private hospitals, for the
majority, the midwife was unable to determine number of visits attended (37.5 per cent)
(Table 18).
Table 18: Number of antenatal care visits attended by women who gave birth in
WA, 2012
Number of Antenatal Care Visits
Birth Site
Nil
1-4
Tertiary
Metro Public
Country Public
Private
Homebirths
Total
9
10
8
60
87
Tertiary
Metro Public
Country Public
Private
Homebirths
Total
Tertiary
Metro Public
Country Public
Private
Homebirths
Total
5-8
Number
250
485
207
219
1
1162
>8
Not Determ
Total
1420
2119
780
1150
26
5495
1239
1852
1359
3409
81
7940
5
30
438
4256
5
4734
2923
4496
2792
9094
113
19418
0.3
0.2
0.3
0.7
0.4
Row Percentage
8.6
48.6
10.8
47.1
7.4
27.9
2.4
12.6
0.9
23.0
6.0
28.3
42.4
41.2
48.7
37.5
71.7
40.9
0.2
0.7
15.7
46.8
4.4
24.4
100.0
100.0
100.0
100.0
100.0
100.0
10.3
11.5
9.2
69.0
100.0
Column Percentage
21.5
25.8
41.7
38.6
17.8
14.2
18.8
20.9
0.1
0.5
100.0
100.0
15.6
23.3
17.1
42.9
1.0
100.0
0.1
0.6
9.3
89.9
0.1
100.0
15.1
23.2
14.4
46.8
0.6
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 13,975 women who had no value reported for number of antenatal care visits attended.
24
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.2.5.
Medical conditions
There were four medical conditions able to be selected for each birth reported. A fifth
option was “Other” described with ICD-10 Codes. More than one-third (36.3 per cent) of
the women who gave birth during 2012 had one or more pre-existing medical
conditions. Women with no pre-existing medical condition totalled 19,970.
The most frequent medical condition was asthma (10.4 per cent) (Table 19).
Table 19: Selected pre-existing medical conditions by plurality of pregnancy of
women who gave birth in WA, 2012
Medical Conditions
Plurality
Single
Multiple
No.
No.
353-358
***
257-261
***
3306
54
630
6
10651
178
13417
216
19509
251
32926
467
1
Essential Hypertension
Pre-existing diabetes
Asthma
Genital Herpes
Other
One or more medical conditions
No Medical Conditions
Total Women
Total
No.
358
261
3360
636
10829
13633
19760
33393
%
1.1
0.8
10.1
1.9
32.4
40.8
59.2
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***. A small number (less than 5) of women who gave birth to triplets have been
included with mothers of twins in the “Multiple” column.
2.2.6.
Medical conditions and obesity
If reported, maternal weight was used with height to calculate a Body Mass Index for
each woman that gave birth in WA in 2012. Women with a BMI of 30 or more were
categorised as obese, these comprised 23.1 per cent of women with a BMI able to be
calculated (Table 14).
A higher proportion of obese women had at least one pre-existing medical condition
(50.2 per cent) reported than women with a low or healthy BMI (39.9 per cent).
The proportion of obese women with essential hypertension (2.5 per cent) was four
times that in other women (0.6 per cent). The proportion of obese women with preexisting diabetes (1.7 per cent) was three times that of other women (0.5 per cent)
(Table 20).
Table 20: Selected pre-existing medical conditions by obesity of women who
gave birth in WA, 2012
Obese
Medical Conditions
Essential Hypertension
Pre-Existing diabetes
Asthma
Genital Herpes
Other
One or more medical conditions
No medical conditions
Total Women
No
No.
147
123
2182
487
7498
9375
14129
23504
%
0.6
0.5
9.3
2.1
31.9
39.9
60.1
100.0
Yes
No.
%
180
2.5
120
1.7
943
13.3
110
1.6
2879
40.7
3550
50.2
3525
49.8
7075
100.0
Total
No.
%
327
1.1
243
0.8
3125
10.2
597
2.0
10377
33.9
12925
42.3
17654
57.7
30579
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 2814 women with no BMI able to be calculated.
Obese women included those that had a BMI of 30 or more.
1
A woman may have more than one pre-existing medical condition.
25
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.2.7.
Complications of pregnancy
There were nine complications defined for reporting each birth. A tenth option was
“Other” described with ICD-10 Codes. Almost one third (32.3 per cent) of the women
who gave birth during 2012, were reported as having one or more complications during
pregnancy.
The most common complications were gestational diabetes (7.0 per cent), premature
rupture of membranes1 (3.5 per cent), urinary tract infection (3.4 per cent), and
threatened miscarriage (2.7 per cent).
The most common complications experienced by women giving birth to twins or higher
multiples were threatened preterm labour (13.9 per cent), premature rupture of
membranes1 (10.7 per cent), gestational diabetes (10.7 per cent) and Pre-eclampsia
(6.0 per cent) (Table 21).
Table 21: Selected complications of pregnancy by plurality of pregnancy for
women who gave birth in WA, 2012
Plurality
Complications of pregnancy2
Threatened miscarriage
Threatened preterm labour
Urinary tract infection
Pre-eclampsia
Antepartum haemorrhage
— placenta praevia
— abruption
— other
Premature rupture of membranes
Gestational diabetes
Other
One or more complications
No complications of pregnancy
Total
Single
No.
903
700
1127
754
134-139
89-93
784
1133
2301
5103
10649
22277
32926
%3
2.7
2.1
3.4
2.3
0.4
0.3
2.4
3.4
7.0
15.5
32.3
67.7
100.0
Multiple
No.
%4
11
2.4
65
13.9
15
3.2
28
6.0
***
***
20
50
50
379
408
59
467
0.4
0.4
4.3
10.7
10.7
81.2
87.4
12.6
100.0
Total
914
765
1142
782
%5
2.7
2.3
3.4
2.3
139
93
804
1183
2351
5482
11057
22336
33393
0.4
0.3
2.4
3.5
7.0
16.4
33.1
66.9
100.0
No.
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***. A small number (less than 5) of women who gave birth to triplets have been
included with mothers of twins in the “Multiple” column.
1
Prelabour rupture of membranes at any gestation, not preterm rupture of membranes
A woman may have more than one complication during pregnancy.
3
Percentage of women with a single birth (n=32,926).
4
Percentage of women having a multiple birth (n= 467).
5
Percentage of women who gave birth (n=33,393).
2
26
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.2.8.
Complications of pregnancy and obesity
Women with a BMI of 30 or more were categorised as obese, these comprised 23.1 per
cent of women with a BMI able to be calculated (Table 14).
A slightly higher proportion of obese women had at least one pregnancy complication
(38.2 per cent) reported than women with a low or healthy BMI (31.8 per cent).
The proportion of obese women with pre-eclampsia (3.5 per cent) was almost twice that
in other women (2.0 per cent) and their proportion with gestational diabetes (11.5 per
cent) was also almost twice that in other women (5.9 per cent) (Table 22).
Table 22: Selected pregnancy complications by obesity in women who gave birth
in WA, 2012
Obese
Complications of pregnancy
1
No
Threatened miscarriage
Threatened preterm labour
Urinary tract infection
Pre-eclampsia
Antepartum haemorrhage
— placenta praevia
— abruption
— other
Premature rupture of membranes
Gestational diabetes
Other
One or more complications
No complications of pregnancy
No.
699
537
781
470
%
3.0
2.3
3.3
2.0
101
63
573
803
1394
3754
7472
16032
0.4
0.3
2.4
3.4
5.9
16.0
31.8
68.2
Total Women
23504
100.0
Yes
No.
140
157
281
246
Total
%
2.0
2.2
4.0
3.5
No.
839
694
1062
716
%
2.7
2.3
3.5
2.3
26
12
166
252
814
1311
2701
4374
0.4
0.2
2.3
3.6
11.5
18.5
38.2
61.8
127
75
739
1055
2208
5065
10173
20406
0.4
0.2
2.4
3.5
7.2
16.6
33.3
66.7
7075
100.0
30579
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Obese women included those that had a BMI of 30 or more.
Excludes 2814 women with no BMI able to be calculated.
27
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.2.9.
Procedures and treatments
In 2012, 96.7 per cent of women who gave birth had a procedure or treatment reported.
The most common procedure was ultrasound examination, with 94.1 per cent of women
having at least one during pregnancy. Intrapartum cardiotocograph was used for 55.2
per cent of women who gave birth.
Reporting about fertility treatment used by women who gave birth commenced in 1994.
The proportion increased from 1.2 per cent in 1994 to 3.4 per cent in 2012. For women
who had multiple births, 14.3 per cent had fertility treatment (Table 23).
Table 23: Procedures and treatments provided to women who gave birth in WA,
2012
Procedures and Treatments1
Fertility treatments
Cervical suture
CVS (placental biopsy)
Amniocentesis
Ultrasound
CTG antepartum
CTG intrapartum
One or more procedures
No procedures
Total Women
Plurality
Single
Multiple
No.
%
No.
%
1065
3.2
67
14.3
92
0.3
9
1.9
136-140
0.4
***
0.4
765
2.3
16
3.4
30980
94.1
456
97.6
7866
23.9
224
48.0
18222
55.3
201
43.0
31844
96.7
462
98.9
1082
3.3
5
1.1
32926
100.0
467
100.0
Total
No.
1132
101
140
781
31436
8090
18423
32306
1087
33393
%
3.4
0.3
0.4
2.3
94.1
24.2
55.2
96.7
3.3
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
A small number of women gave birth to triplets and were included in “Multiple” with twins.
Values <5 are suppressed and indicated with ***. A small number (less than 5) of women who gave birth to triplets have been
included with mothers of twins in the “Multiple” column.
1
A woman may have more than one treatment or procedure during the pregnancy.
28
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.3. Labour
2.3.1.
Onset of labour
Labour is defined as painful, regular uterine contractions that dilate the cervix. The first
stage of labour is timed from when dilatation of the cervix as a result of painful, regular
uterine contractions commenced. The second stage of labour begins when the cervix is
fully dilated and ends with the complete expulsion of the final infant of the pregnancy.
Onset of labour can be spontaneous, induced or never occur. Labour that has a
spontaneous onset can be augmented with medical or surgical procedures. Labour
established spontaneously for 50.1 per cent of the women who gave birth in WA in
2012.
Labour was induced for 29.1 per cent of women who gave birth. Women who did not
experience labour comprised 20.8 per cent (Table 24).
Table 24: Onset of labour and plurality of pregnancy for women who gave birth in
WA, 2012
Onset of labour
Spontaneous
Induced
No labour
Total
Plurality
Single
Multiple
No.
%
No.
%
16588
50.4 129
27.6
9611
29.2 109
23.3
6727
20.4 229
49.0
32926
100.0 467
100.0
Total
No.
16717
9720
6956
33393
%
50.1
29.1
20.8
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
There was a general decrease in the proportion of women who established labour
spontaneously, from a high of 63.4 per cent in 1986, to a low of 49.4 per cent in 2005.
The proportion of women who did not labour was similar each year since 2003 (20.3 per
cent). In the period 1986 to 2003, this proportion doubled from 9.7 per cent (Figure 9
and Table 118).
Figure 9: Onset of labour for women who gave birth in WA, 1986-2012
70
60
40
30
20
10
0
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Proportion of Women
50
spontaneousYear
induction
no labour
29
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.3.2.
Augmentation of labour
Augmentation of labour refers to the use of a medication or procedure to hasten the
process of labour that spontaneously commenced. Augmentation may assist with
improving strength and efficiency of contractions, or to quickly advance labour if the
health of the mother or infant is at risk.
Augmentation by surgical and/or medical intervention was administered to 36.8 per cent
women who established labour spontaneously. Of the women who had their
spontaneous labour augmented, 54.6 per cent progressed to a spontaneous birth, 28.5
per cent had an assisted vaginal birth and 17.0 per cent required delivery by caesarean
section1.
Of the women who had spontaneous onset of labour without augmentation 75.0 per
cent had a spontaneous vaginal birth (Table 25).
Table 25: Labour, augmentation and method of birth for women who gave birth in
WA, 2012
Onset of labour
Spontaneous
- No augmentation
- Augmentation
Induction
Total
Method of birth for first or only infant of
pregnancy
Spontaneous
Assisted
Emergency
vertex
vaginal
caesarean
No.
%
No.
%
No.
%
11276
67.5 2923
17.5 2518
15.1
7915
75.0 1171
11.1 1474
14.0
3361
54.6 1752
28.5 1044
17.0
5404
55.6 2249
23.1 2067
21.3
16680
63.1 5172
19.6 4585
17.3
Total
No.
16717
10560
6157
9720
26437
%
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Assisted vaginal births include all breech vaginal births, vacuum extraction and forceps delivery.
Excludes 6,956 women who did not labour before birth by caesarean section.
1
Women with multiple births were classified by the birth method of the first infant born.
30
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.3.3.
Methods of augmentation
Among women who had an augmentation of spontaneous onset of labour in 2012,
artificial rupture of membranes (ARM) only was reported for 42.5 per cent, and oxytocin
only for 31.2 per cent. A further 25.8 per cent had a combination of oxytocin and ARM
reported. A small proportion, 0.5 per cent of women had only prostaglandin or other
method reported.
Methods of birth after spontaneous onset of labour included Caesarean Section and
may have been before labour achieved full cervical dilatation.
Of women with augmentation of spontaneous labour, 80.8 per cent gave birth in less
than 12 hours while 93.8 per cent of women without augmentation achieved birth in less
than 12 hours.
The highest proportion of women with augmented labour (49.9 per cent) gave birth
within five and 12 hours.
Of the 1,852 women who had a spontaneous onset of labour and a labour duration of
12 hours or more, 64.2 per cent had labour augmented and 64.0 per cent had
augmentation with oxytocin, or ARM, or both in combination (Table 26).
Table 26: Augmentation of spontaneous labour and hours of labour for women
who gave birth in WA, 2012
Type of augmentation
Less than
1 hr
Hours of labour1
1 hr to less 5 hrs to less
than 5 hrs
than 12 hrs
Number
Total
12 hrs or
more
None
724
5182
3986
663
10555
Oxytocin
Art rupture membranes (ARM)
Oxytocin and ARM
Prostaglandin or Other
Total Augmented
92
461
83
875
73
303
3
14
251
1653
Row Percentage
6.9
49.1
950
1348
757
9
3064
419
309
458
3
1189
1922
2615
1591
29
6157
37.8
6.3
100.0
4.8
24.0
3.2
33.5
4.6
19.0
10.3
48.3
4.1
26.8
Column Percentage
49.4
51.5
47.6
31.0
49.8
21.8
11.8
28.8
10.3
19.3
100.0
100.0
100.0
100.0
100.0
36.7
33.1
29.1
1.2
27.9
52.9
18.3
0.8
31.0
44.0
24.7
0.3
35.2
26.0
38.7
0.3
31.2
42.5
25.8
0.5
100.0
100.0
100.0
100.0
100.0
None
Oxytocin
Art rupture membranes (ARM)
Oxytocin and ARM
Prostaglandin or Other
Total Augmented
None
Oxytocin
Art rupture membranes (ARM)
Oxytocin and ARM
Prostaglandin Alone or Other
Total Augmented
Extracted from Midwives’ Notification System on 20 June 2014.
Women who had prostaglandin combined with oxytocin were reported in “oxytocin” groups. Women who had prostaglandin
combined with ARM or other were reported in the “prostaglandin or other” group.
Excludes 5 cases where duration of labour was unknown.
Includes 452 cases which had spontaneous onset labour with 0 minutes of labour. This data combination is unlikely in a clinical
scenario. These cases had no augmentation.
1
Hours of labour include total of first and second stage, and include labours interrupted by Caesarean
Section.
31
Western Australia’s Mothers and Babies 2012, 30th Annual Report
The use of prostaglandin as an agent for augmentation of labour has been modest. Its
use has been reported since 1998 and the trend of use for augmentation is displayed in
Table 27 below.
Table 27: Trend of prostaglandin as augmentation method of spontaneous labour
and hours of labour for women who gave birth in WA, 1998 - 2012
Year
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Hours of labour1
Less than
5 hrs to
More than
5 hrs
12:00
12 hrs
Number
28
14
26
24
21
26
29
11
26
27
6
20
35
7
19
14
5
15
24
11
15
28
8
22
29
7
32
31
15
27
47
17
33
34
9
27
36
9
35
27
8
20
17
5
13
Total
68
71
66
53
61
34
50
58
68
73
97
70
80
55
35
Extracted from Midwives’ Notification System on 20 June 2014.
1
Hours of labour include total of first and second stage, and includes labours interrupted by Caesarean
Section.
32
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.3.4.
Induction of labour
Induction of labour is the process of using medications or procedures to artificially start
labour. Induction is performed to initiate the birth of the infant/s where maternal or fetal
health would be compromised if the birth awaited spontaneous onset of labour.
In 2012, labour was induced by medical and/or surgical means for 29.1 per cent of
women. The methods of induction used were usually combined. Prostaglandin (with or
without “other” method) was used for 10.1 per cent of women induced and it was used
in combination with other named methods for a further 21.6 per cent of women who had
labour induced.
ARM combined with an oxytocin infusion was recorded for 51.1 per cent of the women
whose labour was induced. ARM or oxytocin infusion with or without “other” method was
recorded for 6.7 per cent and 9.2 per cent of women induced, respectively (Table 28).
Table 28: Induction method, birth method for women who gave birth in WA, 2012
Induction Method
Oxytocin
Prostaglandin
Artificial ruptured membrane (ARM)
Oxytocin and ARM
Prostaglandin and ARM
Prostaglandin and Oxytocin
Prostaglandin, Oxytocin and ARM
2
Other Only
Total
Oxytocin
Prostaglandin
Artificial ruptured membrane (ARM)
Oxytocin and ARM
Prostaglandin and ARM
Prostaglandin and Oxytocin
Prostaglandin, Oxytocin and ARM
Other Only
Total
Oxytocin
Prostaglandin
Artificial ruptured membrane (ARM)
Oxytocin and ARM
Prostaglandin and ARM
Prostaglandin and Oxytocin
Prostaglandin, Oxytocin and ARM
Other Only
Total
Method Birth
Assisted
vaginal
Spont
Vaginal
Number
459
495
470
2908
317
100
589
66
5404
Row Percentage
51.5
50.6
72.3
58.6
63.9
36.0
44.5
47.8
55.6
Column Percentage
8.5
9.2
8.7
53.8
5.9
1.9
10.9
1.2
100.0
1
Emergency
caesarean
Total
218
211
87
1196
90
79
341
27
2249
214
273
93
861
89
99
393
45
2067
891
979
650
4965
496
278
1323
138
9720
24.5
21.6
13.4
24.1
18.1
28.4
25.8
19.6
23.1
24.0
27.9
14.3
17.3
17.9
35.6
29.7
32.6
21.3
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
9.7
9.4
3.9
53.2
4.0
3.5
15.2
1.4
100.0
10.4
13.2
4.5
41.7
4.3
4.8
19.0
2.2
100.0
9.2
10.1
6.7
51.1
5.1
2.9
13.6
1.4
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Assisted vaginal births include all breech vaginal births, vacuum extraction and forceps delivery.
Women with multiple methods of induction that included “Other” were counted in “Other” totals in previous annual reports. In this
report these women are included in counts for the named method/s.
1
Women with multiple births were classified by the method of birth of the first infant born.
Women with multiple methods of induction that included “Other” were counted in “Other” totals in
previous annual reports. In this report these women are included in counts for the named method/s.
2
33
Western Australia’s Mothers and Babies 2012, 30th Annual Report
The proportion of women with labour induced with prostaglandin has varied since
reporting began in 1998. Since 2002, the proportion reduced from 38.5 per cent to 31.6
per cent (Table 29).
Table 29: Trend of prostaglandin as induction method and hours of labour for
women who gave birth in WA, 1998 - 2012
Year
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Hours of labour1
Less than
5 hrs to
More than
5 hrs
12:00
12 hrs
Number
1245
255
1214
1333
310
1293
1353
233
1190
1434
223
1170
1459
230
1129
1353
201
1062
1303
192
1001
1525
200
1130
1565
223
1166
1577
239
1139
1600
157
1046
1814
179
1031
1857
207
1121
1930
159
1221
1738
186
1152
Total
2714
2936
2776
2827
2818
2616
2496
2855
2954
2955
2803
3024
3185
3310
3076
Induced
Labour
Proportion of
Inductions
7394
7552
7266
7449
7314
7090
7210
7617
7873
8157
8058
8606
8788
9068
9720
36.7
38.9
38.2
38.0
38.5
36.9
34.6
37.5
37.5
36.2
34.8
35.1
36.2
36.5
31.6
Extracted from Midwives’ Notification System on 20 June 2014.
1
Hours of labour include total of first and second stage, and includes labours interrupted by Caesarean
Section.
34
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.3.5.
Induction of labour by maternity service
In WA in 2012, 29.1 per cent of women had an induction of labour. The tertiary
maternity service (KEMH) had a slightly higher proportion (33.6 per cent) than the whole
of WA (29.1 per cent). Rates at other health services ranged from 16.9 to 41.3 per cent
(Table 30).
Table 30: Induction of labour by maternity service of women who gave birth in
WA, 2012
Onset of Labour
Other1
Induced
Hospital
Armadale Kelmscott
Attadale
Bentley
Glengarry
Goldfields
Great Southern
Home Births
Joondalup HC
Kaleeya
KEMH
Kimberley
Mercy
Midwest
Osborne Park
Peel HC
Pilbara
Rockingham Kwinana
SJOG Bunbury
SJOG Geraldton
SJOG Murdoch
SJOG Subiaco
South West
Swan
Wheatbelt
Total
No.
498
143
174
357
287
154
***
1006
346
1992
128
580
149
472
253
132
412
178
93
595
1160
319
255
35
9715-9720
%
No.
23.5
27.4
20.9
36.2
33.1
27.3
***
33.8
24.5
33.6
21.8
37.5
28.0
28.2
23.3
21.4
26.3
28.9
41.3
29.2
31.4
22.3
22.3
16.9
29.1
1624
379
658
628
580
410
211-216
1969
1068
3936
460
968
383
1202
833
484
1154
438
132
1446
2536
1113
886
172
23669-23673
Total
%
76.5
72.6
79.1
63.8
66.9
72.7
***
66.2
75.5
66.4
78.2
62.5
72.0
71.8
76.7
78.6
73.7
71.1
58.7
70.8
68.6
77.7
77.7
83.1
70.9
No.
2122
522
832
985
867
564
216
2975
1414
5928
588
1548
532
1674
1086
616
1566
616
225
2041
3696
1432
1141
207
33393
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***
1
Other labour onsets included spontaneous labour and no labour.
35
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.3.6.
Analgesia
Analgesia is often administered during labour to reduce the pain experienced while
allowing sensations of touch, pressure and mobility. Anaesthesia provided at time of
birth is described in section 2.4 of this report.
Of the 33,393 women who gave birth 79.2 per cent experienced labour. Of these
women who laboured, 80.1 per cent received single or multiple types of analgesia
during labour. Analgesia via the epidural and/or spinal route was received by 48.7 per
cent women with or without other analgesia.
Inhalation of a mix of Nitrous Oxide without intramuscular, epidural or spinal analgesia
was used by 21.3 per cent of women. Intramuscular narcotic analgesia without epidural
or spinal analgesia was received by 9.0 per cent of women (Table 31).
Table 31: Analgesia during labour and method of birth for women who gave birth
in WA, 2012
Type of Analgesia1
Nitrous oxide
Intra-muscular narcotics
3
Epidural and/or Spinal
Epidural
Spinal
Combined Spinal Epidural
Other
Women with any analgesia
Women with no analgesia
Total women who laboured
Spontaneous
vertex
No.
%
4824
28.9
1865
11.2
5717
34.3
5472
32.8
43
0.3
202
1.2
228
1.4
12634
75.7
4046
24.3
16680 100.0
Method of Birth2
Assisted
Emergency
vaginal
caesarean
No.
%
No.
%
579
11.2
216
4.7
315
6.1
190
4.1
3969
76.7 3195
69.7
3754
72.6 2755
60.1
36
0.7
165
3.6
179
3.5
275
6.0
35
0.7
34
0.7
4898
94.7 3635
79.3
274
5.3
950
20.7
5172
100.0 4585 100.0
Total
No.
5619
2370
12881
11981
244
656
297
21167
5270
26437
%
21.3
9.0
48.7
45.3
0.9
2.5
1.1
80.1
19.9
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Assisted vaginal births include all breech vaginal births, vacuum extraction and forceps delivery.
Among the 21,852 women who gave birth vaginally, 44.3 per cent had an epidural,
spinal or combined spinal epidural during labour, 24.7 per cent received only nitrous
oxide. The proportion of these women who received no pharmacological analgesia
during labour was 19.8 percent (Table 32).
Table 32: Analgesia for women who had vaginal births in WA, 2012
Vaginal Births
Type of analgesia
Nitrous Oxide
Intra-muscular narcotics
Epidural and/or Spinal
Epidural
Spinal
Combined Spinal Epidural
Other
Women with any analgesia
Women with no analgesia
Total women
No.
5403
2180
9686
9226
50
410
263
17532
4320
21852
%
24.7
10.0
44.3
42.2
0.2
1.9
1.2
80.2
19.8
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
1
Analgesia was assigned an ascending rank order of None, Nitrous Oxide, IM Narcotics,
Epidural/Caudal, Spinal, and Combined Spinal/Epidural. The highest Analgesia recorded for each woman
determined her “Type of Analgesia”.
2
Women with multiple births were classified by the method of birth of the first infant born.
3
Count of women who had Epidural, Spinal and/or Combined Spinal Epidural singly or in combination for
analgesia in labour.
36
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.4. Anaesthesia
Anaesthesia is often administered during the birth and differs from analgesia in that its
action is to block sensation, interfere with some reflexes and can impact mobility.
General Anaesthesia also causes loss of consciousness. Each woman who gave birth
may have had nil, one or multiple types of anaesthesia reported. They may also have
had different anaesthesia for each of multiple infants born. Data reported in Table 33
presents one method for each woman. That method is the most intensive method for
first infant born.
Of the 33,393 women who gave birth in WA during 2012, 10,867 (32.5 per cent) had no
anaesthesia, 34.9 per cent received anaesthesia via the epidural route, 11.3 per cent
via the spinal route and 13.0 per cent had combined spinal and epidural anaesthesia. A
further 0.3 per cent had epidural or spinal anaesthesia in combination with a general
anaesthetic. In total, 503 (1.5 per cent) women received general anaesthesia (Table
33).
Table 33: Anaesthesia and method of birth for women who gave birth in WA, 2012
2
Type of
1
Anaesthesia
None
Local to perineum
Spontaneous
Vertex
No.
%
10231
30.6
Method of Birth
Assisted
Elective
vaginal
caesarean
No.
%
No.
%
636
1.9
-
Emergency
caesarean
No.
%
-
Total
No.
%
10867
32.5
955
2.9
644
1.9
-
-
-
-
1599
4.8
10
0.0
135
0.4
-
-
-
-
145
0.4
4817
14.4
3477
10.4
849
2.5
2523
7.6
11666
34.9
34
0.1
65
0.2
2369
7.1
1314
3.9
3782
11.3
184
0.6
174
0.5
2650
7.9
1347
4.0
4355
13.0
***
0.0
***
0.0
101
0.3
388
1.2
503
1.5
Other
439
1.3
37
0.1
-
-
-
-
476
1.4
Total
16670-80
50.0
5168-72
15.5
5969
17.9
5572
16.7
33393
100.0
Pudendal
Epidural
Spinal
Combined Spinal
Epidural
General
Anaesthesia
Extracted from Midwives’ Notification System on 20 June 2014.
Assisted vaginal births include all breech vaginal births, vacuum extraction and forceps delivery
Values <5 are suppressed and indicated with ***.
1
Where both Epidural and Spinal were reported, the case was included in the Combined Spinal Epidural
group.
2
Women with multiple births were classified by the method of birth of the first infant born
37
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Among the 21,852 women who gave birth vaginally, 49.7 per cent did not have
anaesthesia at birth (Table 34).
Epidural and/or spinal anaesthesia was the most frequently administered (40.1 per cent)
method for woman who had a vaginal birth.
Table 34: Anaesthesia for women who had vaginal births in WA, 2012
Vaginal Births
1
Type of anaesthesia
No.
10867
1599
145
8294
99
358
14
476
21852
None
Local anaesthesia to perineum
Pudendal
Epidural
Spinal
Combined Spinal Epidural
General Anaesthesia
Other
Total
%
49.7
7.3
0.7
38.0
0.5
1.6
0.1
2.2
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Among the 11,541 women who gave birth by caesarean section, general anaesthesia
only was received by 3.5 per cent and a further 0.8 per cent had general anaesthesia as
well as a spinal and/or epidural anaesthetic. Most women (95.8 per cent) had regional
anaesthesia, epidural (29.2 per cent), spinal (31.9 per cent) or combined spinal epidural
(34.6 per cent) (Table 35).
Table 35: Anaesthesia for women who had birth by caesarean section in WA, 2012
Caesarean Births
1
Type of Anaesthesia
Epidural
Spinal
Combined Spinal Epidural
General Anaesthesia
Epidural or Spinal as well as General Anaesthesia
Other
Total
No.
3372
3683
3997
401
88
11541
%
29.2
31.9
34.6
3.5
0.8
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Trend data over the period 1986 to 2012 demonstrated a decrease in use of general
anaesthesia (GA) for caesarean birth, particularly for elective caesarean sections. In
1986, GA was used by 42.5 per cent of women who gave birth compared to 4.3 per cent
in 2012. For emergency caesareans, GA was used in 24.2 per cent of cases in 1986
and reduced to a proportion of 3.4 per cent in 2012 (Table 36).
1
Where both Epidural and Spinal were reported, the case was included in the Combined Spinal Epidural
group.
38
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 36: Trend for anaesthesia for women who gave birth by caesarean section
in WA, 1986-2012
Year
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Urgency of Caesarean Section
Emergency Caesarean
Epidural/
Total
Spinal
General
Total
No.
%
No.
%
No.
%
No.
1711
50.3 868 25.5
823 24.2 1691
2046
51.3 1008 25.3
931 23.4 1939
2194
52.6 1047 25.1
929 22.3 1976
2356
52.1 1258 27.8
907 20.1 2165
2493
51.6 1436 29.7
902 18.7 2338
2361
51.9 1432 31.5
755 16.6 2187
2559
53.2 1486 30.9
768 16.0 2254
2763
52.9 1749 33.5
710 13.6 2459
2729
52.2 1891 36.2
603 11.5 2494
2740
54.2 1807 35.7
511 10.1 2318
2865
55.7 1860 36.1
423
8.2 2283
3042
55.8 2004 36.8
407
7.5 2411
3270
55.4 2257 38.2
379
6.4 2636
3310
55.8 2262 38.2
356
6.0 2618
3520
56.1 2439 38.8
321
5.1 2760
3744
55.3 2703 39.9
319
4.7 3022
4004
55.9 2823 39.4
339
4.7 3162
4326
57.6 2856 38.1
322
4.3 3178
4537
55.8 3250 40.0
341
4.2 3591
5067
56.4 3534 39.3
387
4.3 3921
4812
57.6 3225 38.6
322
3.9 3547
4612
54.9 3487 41.5
305
3.6 3792
4665
54.6 3528 41.3
348
4.1 3876
4448
51.3 3842 44.3
382
4.4 4224
4299
50.0 3985 46.3
316
3.7 4301
3776
45.6 4134 49.9
372
4.5 4506
5969
51.7 5184 44.9
388
3.4 5572
Elective Caesarean
Epidural/
Spinal
General
No.
%
No.
%
1089 32.0
622 18.3
1436 36.0
610 15.3
1562 37.5
632 15.2
1774 39.2
582 12.9
1923 39.8
570 11.8
1845 40.6
516 11.3
2070 43.0
489 10.2
2282 43.7
481 9.2
2347 44.9
382 7.3
2371 46.9
369 7.3
2548 49.5
317 6.2
2761 50.6
281 5.2
3008 50.9
262 4.4
3100 52.3
210 3.5
3289 52.4
231 3.7
3563 52.7
181 2.7
3844 53.6
160 2.2
4159 55.4
167 2.2
4385 53.9
152 1.9
4913 54.7
154 1.7
4698 56.2
114 1.4
4495 53.5
117 1.4
4525 53.0
140 1.6
4338 50.0
110 1.3
4200 48.8
99 1.2
3658 44.2
118 1.4
5868 50.8
101 0.9
Total
Caesareans
%
No.
49.7 3402
48.7 3985
47.4 4170
47.9 4521
48.4 4831
48.1 4548
46.8 4813
47.1 5222
47.8 5223
45.8 5058
44.3 5148
44.2 5453
44.6 5906
44.2 5928
43.9 6280
44.7 6766
44.1 7166
42.4 7504
44.2 8128
43.6 8988
42.4 8359
45.1 8404
45.4 8541
48.7 8672
50.0 8600
54.4 8282
48.3 11541
Extracted from Midwives’ Notification System on 20 June 2014.
39
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.5. Fetal presentation
The majority, 94.7 per cent of infants born from singleton births were vertex
presentations, of these, 68.2 per cent were born vaginally.
Among infants born from singleton pregnancies, 3.8 per cent had breech presentations.
Of breech singleton infants, 33.6 per cent were by emergency caesarean section and
56.5 per cent by elective caesarean section.
Of singleton infants, 12.3 per cent were born by vacuum extraction and 2.9 per cent by
forceps. There were 125 breech infants born vaginally with or without breech
manoeuvres or application of forceps to aftercoming head (Table 37).
Table 37: Fetal presentation and method of birth for singleton infants born in WA,
2012
1
Method of Birth
Spontaneous
Vacuum
Forceps
Breech Vaginal
Elective Caesarean
Emergency Caesarean
Total
Spontaneous
Vacuum
Forceps
Breech Vaginal
Elective Caesarean
Emergency Caesarean
Total
Spontaneous
Vacuum
Forceps
Breech Vaginal
Elective Caesarean
Emergency Caesarean
Total
Fetal Presentation
2
Vertex
Breech
Other
No.
No.
No.
16319
252
4017
42
931
16
125
5032
712
61
4889
423
107
31188
1260
478
Column Percentage
52.3
52.7
12.9
8.8
3.0
3.3
9.9
16.1
56.5
12.8
15.7
33.6
22.4
100.0
100.0
100.0
Row Percentage
98.5
1.5
99.0
1.0
98.3
1.7
100.0
86.7
12.3
1.1
90.2
7.8
2.0
94.7
3.8
1.5
Total
No.
16571
4059
947
125
5805
5419
32926
50.3
12.3
2.9
0.4
17.6
16.5
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
1
Where multiple methods of birth were reported for an infant, the highest method of birth was reported
with ascending rank order being Spontaneous, Vacuum, Forceps, Breech Vaginal, Caesarean Section
2
Other Cephalic presentations like Brow and Face are included in “Other” with shoulder or compound
presentations
40
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.5.1.
Vertex presentation and method of birth in maternity services
Women with a vertex presentation of the first or only infant of the pregnancy may be
more likely to have a spontaneous vaginal birth unless they have a history of caesarean
section or complication of pregnancy or labour requiring caesarean section.
In WA in 2012, just over half (52.1 per cent) of the women who gave birth to an infant
with a vertex presentation had a spontaneous vaginal birth. The tertiary maternity
service (KEMH) had a slightly lower proportion than the whole of WA (51.9 per cent).
Rates at other metropolitan health services ranged from 29.2 to 68.7 per cent (Table
38).
Table 38: Method of birth and maternity service of infants born with vertex
presentation in WA, 2012
Hospital
Armadale Kelmscott
Attadale
Bentley
Glengarry
Goldfields
Great Southern
Joondalup
Kaleeya
KEMH
Kimberley
Mercy
Midwest
Osborne Park
Peel
Pilbara
Rockingham Kwinana
SJOG Bunbury
SJOG Geraldton
SJOG Murdoch
SJOG Subiaco
South West
Swan Districts
Wheatbelt
Homebirths
Total
Method of Birth
Other1
Spont Vaginal
No.
%
No.
%
1318
65.5
693
34.5
208
42.9
277
57.1
445
56.0
349
44.0
341
36.4
595
63.6
504
61.5
315
38.5
372
68.5
171
31.5
1482
51.7
1382
48.3
769
57.0
581
43.0
2809
51.9
2607
48.1
371
66.8
184
33.2
640
43.4
833
56.6
345
68.7
157
31.3
879
55.4
709
44.6
618
59.1
427
40.9
358
61.2
227
38.8
974
65.4
515
34.6
278
47.9
302
52.1
130
59.6
88
40.4
561
29.2
1361
70.8
1069
30.4
2445
69.6
861
63.5
494
36.5
751
68.7
342
31.3
129
67.2
63
32.8
216
100.0
16428
52.1
15117
47.9
Total
No.
2011
485
794
936
819
543
2864
1350
5416
555
1473
502
1588
1045
585
1489
580
218
1922
3514
1355
1093
192
216
31545
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Includes pregnancies of multiple plurality if first infant was vertex.
Includes infants born before arrival.
Includes infants born at non-maternity sites.
1
Other methods of birth include breech vaginal, vacuum, forceps and caesarean section.
41
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.6. Method of birth
In 2012, half of the women had spontaneous vertex births (50.0 per cent). Caesarean
section was the birth method for 34.6 per cent of women who gave birth. This
comprised 17.9 per cent elective caesarean section and 16.7 per cent emergency
caesarean section (Table 39).
Women with a multiple pregnancy (more than one fetus) were more likely to have birth
by caesarean section. In 2012, of the women with a multiple pregnancy, 67.9 per cent
gave birth by caesarean section (Table 39).
Table 39: Method of birth and plurality of pregnancy for women who gave birth in
WA, 2012
Plurality
Single
No.
16571
125
4059
947
5805
5419
32926
Method of birth of first infant
Spontaneous Vertex
Breech
Vacuum
Forceps
Elective Caesarean
Emergency Caesarean
Total
Multiple
Total
No.
%
No.
%
109
23.3 16680
50.0
10
2.1
135
0.4
21
4.5 4080
12.2
10
2.1
957
2.9
164
35.1 5969
17.9
153
32.8 5572
16.7
467
100.0 33393 100.0
%
50.3
0.4
12.3
2.9
17.6
16.5
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
The incidence of both elective and emergency caesarean section has more than tripled
over the 32 years with data available. While the rate of elective caesarean section
appears to have plateaued in the last five years, the rate of emergency caesarean
section continued to rise (Figure 10). Assisted vaginal birth (breech, vacuum or forcep)
or caesarean section accounted for 50.0 per cent of women who gave birth in WA in
2012.
Figure 10: Trend for method of birth for women who gave birth in WA, 1980-2012
70
65
60
Proportion of women
55
50
45
40
35
30
25
20
15
10
5
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1985
1986
1984
1983
1982
1981
1980
0
Year
Spont
Assisted Vaginal
Elect CS
Emerg CS
Breech, Vacuum and Forceps for first or only infant were combined to determine “Assisted Vaginal” number of women.
42
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Of 14,312 women who gave birth for the first time in 2012, 34.9 per cent had a
caesarean section.
Of women who gave birth in 2012 with a history of caesarean section, 329 had a vaginal
birth for their last birth and 5,420 had their last birth by caesarean section. Vaginal birth
was achieved by 12.1 per cent of these women in 2012 (Table 40).
Table 40: Method of birth by history of caesarean section for women who gave
birth in WA, 2012
Method of Birth
Previous birth
Method
Spontaneous
No.
Breech
Instrumental
Elective
Caesarean
Emergency
Caesarean
%
No.
%
No.
%
No.
%
No.
%
5443
38.0
52
0.4
3826
26.7
1441
10.1
3550
Previous births,
no caesareans
10729
80.5
60
0.5
1041
7.8
701
5.3
No previous
caesarean
16172
58.5
112
0.4
4867
17.6
2142
Previous
caesarean, last
birth vaginal
197
59.9
3
0.9
18
5.5
Previous
caesarean, last
birth caesarean
311
5.7
17
0.3
155
Previous
caesarean
508
8.8
20
0.3
16680
50.0
132
0.4
First Birth
Total
Total
No.
%
24.8
14312
100.0
801
6.0
13332
100.0
7.7
4351
15.7
27644
100.0
62
18.8
49
14.9
329
100.0
2.9
3765
69.5
1172
21.6
5420
100.0
173
3.0
3827
66.6
1221
21.2
5749
100.0
5040
15.1
5969
17.9
5572
16.7
33393
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
43
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.6.1.
Caesarean section by maternity service
The tertiary maternity service in Western Australia (KEMH) had 35.6 per cent of women
giving birth by caesarean section. Rural health services’ caesarean section rates ranged
between 20.0 per cent in the Goldfields and 31.8 per cent in the Pilbara. Caesarean
section rates at private health services ranged between 25.8 and 57.0 per cent (Table
41).
Table 41: Caesarean section by maternity service of women who gave birth in
WA, 2012
Method of Birth
Vaginal Birth
Hospital
Armadale Kelmscott
Attadale
Bentley
Glengarry
Goldfields
Great Southern
Homebirths
Joondalup
Kaleeya
KEMH
Kimberley
Mercy
Midwest
Osborne Park
Peel
Pilbara
Rockingham Kwinana
SJOG Bunbury
SJOG Geraldton
SJOG Murdoch
SJOG Subiaco
South West
Swan Districts
Wheatbelt
Total
No.
1608
317
584
496
694
419
217
1941
983
3819
446
931
409
1137
754
420
1192
389
167
877
1956
1062
878
156
21852
%
75.8
60.7
70.2
50.4
80.0
74.3
100.0
65.2
69.5
64.4
75.9
60.1
77.0
67.9
69.4
68.2
76.1
63.1
74.2
43.0
52.9
74.2
77.0
75.4
65.4
Caesarean
No.
514
205
248
489
173
145
0
1034
431
2109
142
617
122
537
332
196
374
227
58
1164
1740
370
263
51
11541
%
24.2
39.3
29.8
49.6
20.0
25.7
0.0
34.8
30.5
35.6
24.1
39.9
23.0
32.1
30.6
31.8
23.9
36.9
25.8
57.0
47.1
25.8
23.0
24.6
34.6
Total
No.
2122
522
832
985
867
564
217
2975
1414
5928
588
1548
531
1674
1086
616
1566
616
225
2041
3696
1432
1141
207
33393
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
44
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.7. Hours of established labour
For women who gave birth vaginally following a spontaneous onset of labour, 57.1 per
cent had duration of labour of 6 hours or less and 33.4 per cent laboured between 6 and
12 hours. Within 12 hours of spontaneous onset of labour, 90.4 per cent of these
women had given birth.
Proportionally, more women who gave birth vaginally following an induction of labour
had a labour duration of 12 hours or less (96.2 per cent) than those with spontaneous
onset of labour (Table 42 and Figure 11).
Table 42: Onset of labour by hours of labour for women who gave birth vaginally
in WA, 2012
Hours of labour
Less than 1 hour
1 to 6 hours
6:01 to 12 hours
12:01 to 18 hours
18:01 to 24 hours
More than 24 hours
Total
Onset of labour
Spontaneous
Induction
No.
%
No.
%
306
2.2
246
3.2
7788
54.9
5110
66.8
4741
33.4
2009
26.3
1100
7.7
243
3.2
200
1.4
33
0.4
59
0.4
11
0.1
14194
100.0
7652
100.0
Total
No.
%
552
2.5
12898
59.0
6750
30.9
1343
6.1
233
1.1
70
0.3
21846
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 6 cases where duration of labour was not reported.
Figure 11: Onset of labour by hours of labour for women who gave birth vaginally
in WA, 2012
80.0
66.8
Proportion of Women
70.0
60.0
54.9
50.0
40.0
33.4
26.3
30.0
20.0
10.0
7.7
2.2
3.2
3.2
1.4
0.4
0.4
0.1
0.0
Less than 1 hour
1 to 6 hours
6:01 to 12
hours
12:01 to 18
hours
18:01 to 24
hours
More than 24
hours
Hours of Established Labour
Spontaneous
Induction
45
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.8. Complications of labour and birth
2.8.1.
Plurality of pregnancy
In 2012, 38.3 per cent of women who had a singleton birth had no complications during
labour and birth (Table 43).
Of the women who had a multiple birth, 5.4 per cent had no complications during labour
and birth.
There were differences in the rate of complications during labour and birth between
women with singleton and multiple births. Precipitate delivery, fetal compromise, cord
tight around neck, disproportion and failure to progress in labour were reported more
often for women with singleton than multiple births. Prolapsed cord, primary postpartum
haemorrhage (PPH) and manual removal of placenta were recorded more often for
multiple births than singleton births.
The most common complications reported were primary PPH (19.3 per cent), previous
caesarean section (17.1 per cent) and fetal compromise (10.2 per cent) (Table 43).
Table 43: Complications of labour and birth by plurality of pregnancy for women
who gave birth in WA, 2012
Complications
1
of labour and birth
Precipitate delivery
Fetal compromise
Prolapsed cord
Cord tight around neck
Cephalopelvic disproportion
Primary Postpartum Haemorrhage
≤500mLs (PPH)
Retained placenta manual removal
Persistent occipito posterior
Shoulder dystocia
Failure to progress <=3cms
Failure to progress >3cms
Previous caesarean section
Other
Any complication
No complications of labour and birth
Total Women
Singleton
No.
1245
3357
41
584
263
6245
333
575
497
2157
1589
5638
10770
20328
12598
32926
Plurality of Birth
Multiple
%
No.
3.8
8
10.2
35
0.1
***
1.8
***
0.8
19.0
1.0
1.7
1.5
6.6
4.8
17.1
32.7
61.7
38.3
100.0
194
7
7
18
15
87
427
442
25
467
%
1.7
7.5
***
***
41.5
1.5
1.5
3.9
3.2
18.6
91.4
94.6
5.4
100.0
Total
No.
%
1253
3.8
3392
10.2
***
***
***
***
263
0.8
6439
340
582
497
2244
1604
5725
11197
20770
12623
33393
19.3
1.0
1.7
1.5
6.7
4.8
17.1
33.5
62.2
37.8
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
These data include reasons for instrumental delivery or caesarean section of the first or only infant born from the pregnancy.
Values <5 are suppressed and indicated with ***.
1
A woman may have more than one complication of labour and birth
46
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.8.2.
Obesity
For women who gave birth in 2012, maternal weight and height were recorded for a
large proportion (91.6 per cent). For women without BMI able to be determined, the
complications of precipitate delivery, prolapsed cord, cord tight around neck and manual
removal of placenta were more common than in women with a BMI determined, while
PPH and failure to progress in labour were less common.
Of all women who gave birth, 21.2 percent had a BMI calculated as greater than 30
(recorded as obese). A higher proportion of these women had one or more
complications of labour and birth reported (71.4 per cent) compared with women who
had a BMI less than 30 (59.8 per cent) or no BMI reported (59.3 per cent).
Incidence of PPH (26.9 per cent) and history of Caesarean Section (23.4 per cent) was
50 per cent higher in obese women than in women with BMI less than 30 (17.9 and 15.3
per cent respectively) (Table 44).
Table 44: Complications of labour and birth by obesity in women who gave birth
in WA, 2012
Complications
1
of labour and birth
Precipitate delivery
Fetal compromise
Prolapsed cord
Cord tight around neck
Cephalopelvic disproportion
Primary Postpartum Haemorrhage
≥500mLs (PPH)
Retained placenta manual removal
Persistent occipito posterior
Shoulder dystocia
Failure to progress <=3cms
Failure to progress >3cms
Previous caesarean section
Other
Any complication
No complications of labour and birth
Total Women
Proportion of Total Women
BMI <30
No.
%
750
3.2
2356
10.0
30
0.1
407
1.7
170
0.7
4207
225
375
332
1661
1080
3596
7814
14047
9457
23504
70.4
17.9
1.0
1.6
1.4
7.1
4.6
15.3
33.2
59.8
40.2
100.0
Maternal Obesity
BMI ≥30
BMI N/A
No.
%
No.
%
334
4.7
169
6.0
782
11.1
254
9.0
10
0.1
8
0.3
117
1.7
62
2.2
63
0.9
30
1.1
1905
75
153
126
455
424
1644
2725
5055
2020
7075
21.2
26.9
1.1
2.2
1.8
6.4
6.0
23.2
38.5
71.4
28.6
100.0
327
40
54
39
59
100
485
658
1668
1146
2814
8.4
11.6
1.4
1.9
1.4
2.1
3.6
17.2
23.4
59.3
40.7
100.0
Total
No.
%
1253
3.8
3392
10.2
48
0.1
586
1.8
263
0.8
6439
340
582
497
2175
1604
5725
11197
20770
12623
33393
100.0
19.3
1.0
1.7
1.5
6.5
4.8
17.1
33.5
62.2
37.8
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
These data include reasons for instrumental delivery or caesarean section of the first or only infant born from the pregnancy.
N/A = Not Available
1
A woman may have nil, one or more complications of labour and birth reported
47
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.8.3.
Primary postpartum haemorrhage
The overall primary postpartum haemorrhage (PPH) rate for 2012 was 19.3 per cent
(Table 44).
The proportion of women who had a PPH of 500 mLs or more has risen each year from
1.7 per cent in 1986. In particular women who had birth by Caesarean Section, the
proportion with PPH reported increased from 1.2 in 1986 to 35.5 per cent in 2012
(Figure 12).
This increase should be interpreted with caution. The amount of blood loss at birth
required to be reported as a PPH was 500 mLs or more. In 2012, the introduction of a
new reporting system at many public maternity services automated the reporting of
blood loss recorded as 500 mLs or more as a PPH.
Figure 12: Trend for primary postpartum haemorrhage for women who gave birth
in WA, 1986-2012
35
Proportion of Women with birth method
30
25
20
15
10
5
0
PPH (>=500mLs) for CS
PPH (>=500mLs) for VB
PPH (>=500mLs) All Women
48
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.8.4.
Reason for caesarean section
The Midwives Notification System did not collect a specified reason for caesarean
section. However, midwives were required to include the reason for caesarean section
when reporting complications of labour and birth. More than one complication may have
been recorded and women who gave birth by caesarean section had at least one
complication reported.
The most frequently reported complication in 2012 for women who gave birth by
caesarean section was “previous caesarean section” (44.4 per cent). A lack of progress
in labour was reported for 18.5 per cent of women having caesarean sections. Fetal
distress occurred in 16.0 per cent of women giving birth by caesarean section (Table
45).
Table 45: Frequent complications of labour and birth for women who gave birth
by caesarean section in WA, 2012
1
Complications of Labour and Birth
Previous caesarean section
No progress in labour
Fetal distress
Other Reasons
Women with birth by Caesarean Section and one or more of above
Women with birth by Caesarean Section and other complication
Total Women with birth by CS
No.
5126
2139
1850
1674
10509
1032
11541
%
44.4
18.5
16.0
14.5
91.1
8.9
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
2.8.5.
Accoucheur
A woman may give birth to more than one infant. Each infant of a birth may have had
one or more birth attendants (accoucheurs) reported. These data report the first or only
birth attendant for the first or only infant resulting from a pregnancy.
Table 46 displays the birth attendant in order of reporting value from highest to lowest.
Midwives and obstetricians were the birth attendant of highest value reported in almost
equal numbers of birth performing 34.8 and 36.0 per cent respectively. Other medical
officers performed 26.6 per cent. A midwife, or a supervised student, was the
accoucheur for 73.7 per cent (12,284) of women who had a spontaneous vertex birth.
Table 46: Method of birth and accoucheur for women who gave birth in WA, 2012
Accoucheur
Obstetrician
2
Other Medical Officer
Midwife
Student
Self/no attendant
Other
Total
Spontaneous
Vertex
No.
%
1918
11.5
2320
13.9
11546
69.3
738
4.4
49
0.3
96
0.6
16667 100.0
Method of Birth
Assisted
Elective
Vaginal
Breech Caesarean
No.
% No.
%
No.
%
2538 50.2 26 19.7 4270 71.5
2515 49.8 29 22.0 1699 28.5
- 73 55.3
- ***
***
- ***
***
- ***
***
5053 100.0 132 100.0 5969 100.0
Emergency
Caesarean
No.
%
3265 58.6
2307 41.4
5572 100.0
Total
No.
%
12017
36.0
8870
26.6
11619
34.8
735-740
47-51
97-101
0.3
33393 100.0
Extracted from Midwives’ Notification System on 20 June 2014.
The one birth attendant reported was determined from the order of values reported e.g. If Obstetrician value of 1 reported then a
reported midwife value of 2 for the same infant is ignored.
Values <5 are suppressed and indicated with ***, some values in the same row/column are provided as a range to prevent
calculation of the suppressed value.
1
A woman may have nil, one or more complications of labour and birth reported
2
Other Medical Officer includes GP Obstetricians, Obstetric Registrars and Residents, District Medical
Officers etc.
49
Western Australia’s Mothers and Babies 2012, 30th Annual Report
2.9. Repair of perineum and/or vagina
Among the 21,838 women who gave birth vaginally, there were 35.9 per cent with an
intact perineum, 20.7 per cent had an episiotomy performed, and 2.3 per cent had a 3rd
or 4th degree tear traumatising the anal sphincter. For 19.8 per cent (892) of the women
who had an episiotomy, a tear extended the episiotomy. Instrumental births had the
highest rates for episiotomy and anal sphincter trauma (Table 47).
Table 47: Method of birth and perineal status for women who gave birth in WA,
2012
Method of birth
None
Spontaneous
Vacuum
Forceps
Breech
Total
7179
503
51
111
7844
Spontaneous
Vacuum
Forceps
Breech
Total
43.1
12.3
5.3
84.1
35.9
Perineal status
1 or 2 degree
Number
1705
7128
2054
1330
744
82
8
11
4511
8551
Row Percentage
10.2
42.8
50.4
32.6
77.5
8.5
6.1
8.3
20.7
39.2
Episiotomy
1
3 or 4 degree
Other
Total
276
140
76-81
***
497
380
51-55
***
435
16668
4078
960
130-134
21838
1.7
3.4
8.2
1.5
2.3
2.3
1.3
0.4
0.0
2.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excluded are 14 women who had a vaginal birth with no perineal status reported.
Birth method presented is for the singleton infant or first infant of a multiple birth, perineal status determined after birth of all infants.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
1
Includes 892 women who had an episiotomy plus tear reported. The degree of the tear is unknown.
50
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Earlier trends indicated a decreasing rate of episiotomy from 29.9 per cent in 1993 to
17.1 per cent in 2008, this trend has reversed and attained 20.7 per cent in 2012. The
proportion of women with 1st or 2nd degree perineal trauma increased since 1993
attaining 39.2 per cent in 2012. The rate per 100 women of anal sphincter trauma
increased from a low of 0.8 per cent in 2001 to a high of 2.3 per cent in 2012. The
change in proportion of women with “Other” perineal status is unable to be explained
(Figure 13).
Figure 13: Trend for perineal status for women who gave birth vaginally in WA,
1993-2012
40
35
30
Percent
25
20
15
10
5
0
19931994199519961997199819992000200120022003200420052006200720082009201020112012
Intact
1 or 2 degree tear
Year
Episiotomy
Other
3 or 4 degree tear
51
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3. Aboriginal mothers and infants
In 2012, there were 1,630 Aboriginal women who gave birth in WA. These women
comprised 4.9 per cent of all women giving birth (Table 46). This was a decrease of 93
Aboriginal women (5.4 per cent) from the number that gave birth in 2011.
Table 48: Aboriginal status of women who gave birth in WA, 2012
Aboriginal Status
Aboriginal
non-Aboriginal
Total
Number
1630
31763
33393
Percentage
4.9
95.1
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
3.1. Maternal age
Maternal age for all women ranged from 13 to 50 years with a mean of 29.7 years and a
median of 30 years. Aboriginal women who gave birth were younger with a mean age at
birth of 24.8 years, median age of 24 years and most common age (mode) was 21
years (Table 49).
Table 49: Maternal age summary statistics and Aboriginal status for women who
gave birth in WA, 2012
Maternal age (years)
Minimum age
Maximum age
Mean age
Median age
Mode age
Standard Deviation of age
Aboriginal Status of mother
Aboriginal
non-Aboriginal
13
13
45
50
24.8
30.0
24
30
21
30
6.3
5.5
Total
13
50
29.7
30
30
5.6
Extracted from Midwives’ Notification System on 20 June 2014.
For Aboriginal women who gave birth in 2012, the highest proportion were in the 20 to
24 year age group (32.3 per cent). Among non-Aboriginal women, the highest
proportion of those that gave birth in 2012 were in the 30 to 34 year age group (33.2 per
cent) (Table 50).
Table 50: Maternal age and Aboriginal status of women who gave birth in WA,
2012
Maternal age
<=15
16
17
18
19
<=19
20-24
25-29
30-34
35-39
>=40
Total
Aboriginal status of mother
Aboriginal
non-Aboriginal
No.
%
No.
%
21
1.3
19
0.1
45
2.8
61
0.2
72
4.4
182
0.6
101
6.2
280
0.9
111
6.8
450
1.4
350
21.5
992
3.1
527
32.3
4385
13.8
399
24.5
9145
28.8
219
13.4
10531
33.2
108
6.6
5463
17.2
27
1.7
1247
3.9
1630
100.0
31763
100.0
Total
No.
40
106
254
381
561
1342
4912
9544
10750
5571
1274
33393
%
0.1
0.3
0.8
1.1
1.7
4.0
14.7
28.6
32.2
16.7
3.89
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
The proportion of teenaged mothers among all Aboriginal women who gave birth (21.5
per cent) was more than six times greater than the corresponding group’s proportion
among non-Aboriginal women (3.1 per cent). Aboriginal women aged 30-34 years
comprised 13.4 per cent, half the proportion of non-Aboriginal women in the same age
group (33.2 per cent) (Figure 14).
52
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Figure 14: Maternal age distribution by Aboriginal status for women who gave
birth in WA, 2012
Proportion of all women giving birth (%)
35.0
33.2
32.3
28.8
30.0
24.5
25.0
21.5
20.0
17.2
13.8
15.0
13.4
10.0
6.6
5.0
3.9
3.1
1.7
0.0
≤ 19
20–24
25–29
30–34
Maternal Age
Aboriginal
35–39
≥ 40
non-Aboriginal
Over the past 30 years, the proportion of women who gave birth in WA that were
Aboriginal remained relatively consistent, ranging from 5.0 per cent in 1980 to 6.8 per
cent in 2002 and 4.9 per cent in 2012 (Table 113).
53
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.1.1.
Age-specific birth rates
Population data for Western Australian Aboriginal and non-Aboriginal childbearing aged
women were available as projected data for 2012 at time of reporting.
The age-specific birth rate of Aboriginal women was 89.2 per 1000 women of childbearing age. This rate has declined from 126.0 in 1990 but was higher than the agespecific rate of 64.3 per 1000 non-Aboriginal women of child-bearing age.
For the 15–19 year age group, the age specific birth rate for Aboriginal women (86.8 per
1000) was more than six times the rate for non-Aboriginal women (13.5 per 1000).
For the 20–24 year age group, the birth rate for Aboriginal women (144.1 per 1000
women) was more than twice the rate for non-Aboriginal women (51.8 per 1000
women).
For women in the 30–34 year age group, the birth rate for Aboriginal women (84.9 per
1000) was three quarters the rate for non-Aboriginal women (130.4 per 1000 women).
For women in the 40-44 year age group, the birth rate for Aboriginal women (11.2 per
1000) was similar to the rate for non-Aboriginal women (14.9 per 1000 women) (Table
51 and Figure 15).
Table 51: Maternal age-specific birth rates by Aboriginal status of women who
gave birth in WA, 2012
Age
15–19
20–24
25–29
30–34
35–39
40–44
Total
Gave
Birth
350
527
399
219
108
27
1630
Aboriginal Status of mother
Aboriginal
non-Aboriginal
Birth
Gave
Birth
1
2
2
Pop’n
rate
Birth
Pop’n
rate
4033
86.8
992
73212
13.5
3657
144.1
4385
84591
51.8
3096
128.9
9145
89270 102.4
2579
84.9 10531
80733 130.4
2509
43.0
5463
82534
66.2
2402
11.2
1247
83828
14.9
18276
89.2 31763
494168
64.3
Total
Gave
Birth
1342
4912
9544
10750
5571
1274
33393
Pop’n
77245
88248
92366
83312
85043
86230
512444
Birth
2
rate
17.4
55.7
103.3
129.0
65.5
14.8
65.2
Data Extracted from Midwives’ Notification System on 20 June 2014.
The 15-19 year age group includes births to mothers younger than 15 years of age. The 40-45 age group includes births to mothers
aged 45years or more.
1
Source of population data: Health Statistics Calculator, Nov 2014
2
Age-Specific Birth Rate — the total number of births in one year per 1000 women of the same age
group.
54
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Figure 15: Maternal age-specific birth rates by Aboriginal status for women who
gave birth in WA, 2012
160
144.1
140
128.9
130.4
Number per 1000
120
102.4
100
86.8
84.9
80
66.2
60
51.8
43.0
40
20
14.9
11.2
13.5
0
15–19
20–24
25–29
30–34
Maternal age groups
Aboriginal non-Aboriginal
35–39
40–44
Trend data for the period 1983 to 2012 indicate that the age-specific birth rate for all
women in the age group 15 to 19 years varied between a high of 27.6 births per 1000
women in 1983 and a low of 17.4 in 2012. The birth rate for all women aged 35 to 44
increased from a low of 14.5 in 1983 to 40.9 per 1000 women in 2008. The rate for 2012
was 40.0 per 1000 women (Table 113).
For Aboriginal women, the age-specific birth rate for teenaged women has almost
halved since 1988, from 164.6 to 86.8 per 1000 in 2012. The birth rate for 20 to 34 year
old Aboriginal women has varied only slightly since 1983, starting at 134.4 in 1983 and
being 122.7 per 1000 women in 2012. Older Aboriginal women, aged 35 years or more
had a birth rate that increased from 15.5 in 1983 to 27.5 per 1000 in 2012 varying in
those years from a low of 13.7 to a high of 33.6 in 2007 (Figure 16 and Table 113).
Generally the age-specific birth rate in 2012 of 64.3 per 1000 non-Aboriginal women
almost attained the 1983 rate of 69.4 per 1000. For Aboriginal women, the trend of agespecific birth rate has declined over the same period from 119.0 to 89.2 per 1000
Aboriginal women (Figure 16 and Table 113).
Figure 16: Trend in maternal age-specific birth rates by Aboriginal status for
women who gave birth in WA, 1983-2012
55
Western Australia’s Mothers and Babies 2012, 30th Annual Report
180
Women who gave birth per 1000
160
140
120
100
80
60
40
20
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
0
Aboriginal 15-19 years
Aboriginal 20-34 years
Aboriginal 35-44 years
Aboriginal Total
Non-Aboriginal 15-19 years
Non-Aboriginal 20-34 years
Non-Aboriginal 35-44 years
Non-Aboriginal Total
3.2. Health region of residence
Aboriginal women accounted for 4.9 per cent of women who gave birth in 2012.
However, the proportion of women who were Aboriginal varied across health regions of
residence.
Women who resided in metropolitan areas had the lowest proportion of Aboriginal
women with 1.7 per cent in the north health area and 2.8 per cent in the south. Women
who lived in the country health regions had a 14.4 per cent proportion of Aboriginal
women with the range of proportion between 2.9 per cent in the Southwest and 57.6 per
cent in the Kimberley.
Of the Aboriginal women who gave birth and resident in Western Australia, 35.9 per
cent were metropolitan residents and 64.1 per cent lived in a country health region. For
non-Aboriginal women resident in Western Australia, 80.5 per cent lived in a
metropolitan health region, 19.5 per cent in a country health region (Table 52).
56
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 52: Health region of residence and Aboriginal status of women who gave
birth in WA, 2012
Health region of residence
Metropolitan
North
South
Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Metropolitan
North
South
Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Metropolitan
North
South
Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Aboriginal Status of mother
Aboriginal
non-Aboriginal
Numbers
584
25531
232
13091
352
12440
1044
6188
102
857
49
662
392
289
177
714
182
693
62
2102
80
871
1628
31719
Row Percentage
2.2
97.8
1.7
98.3
2.8
97.2
14.4
85.6
10.6
89.4
6.9
93.1
57.6
42.4
19.9
80.1
20.8
79.2
2.9
97.1
8.4
91.6
4.9
95.1
Column Percentage
35.9
80.5
14.4
41.3
21.6
39.2
64.1
19.5
6.3
2.7
3.0
2.1
24.1
0.9
10.9
2.3
11.2
2.2
3.8
6.6
4.9
2.7
100.0
100.0
Total
26115
13323
12792
7232
959
711
681
891
875
2164
951
33347
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
78.3
40.0
38.4
21.7
2.9
2.1
2.0
2.7
2.6
6.5
2.9
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
46 women, including 2 who were Aboriginal, were excluded as their residence was not within Western Australia1.
1
Permanent residence reported was an external Australian Territory like Christmas Island, other
Australian state or other country.
57
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.3. Care during pregnancy
2012 was the second year that midwives could report gestational age at first antenatal
care visit. The proportion of cases reported that had no determined gestational age
decreased from 10.0 to 8.0 per cent of records. The proportion of women who did not
attend antenatal care also decreased, from 1.9 per cent in 2011 to 0.2 per cent in 2012.
For Aboriginal women who gave birth in 2012, more than one third commenced
antenatal care in the first trimester (34.4 per cent). They were half as likely as nonAboriginal women to commence antenatal care in the first trimester (RR 0.6) and were
almost 15 times more likely to not attend antenatal care (RR 14.8). Aboriginal women
were more likely to have this data not determined (relative risk 1.5) (Table 53).
Table 53: Gestation at first antenatal care visit and Aboriginal status of women
who gave birth in WA, 2012
Aboriginal Status
1-12
Aboriginal
non-Aboriginal
Total
560
17954
18514
Aboriginal
non-Aboriginal
Total
34.4
56.5
55.4
Aboriginal
non-Aboriginal
Gestational Age Groups (weeks)
Did not
13–24
>24
Attend
Number
525
9027
9552
Percentage
32.2
28.4
28.6
Relative Risk (RR)
0.6
1.1
1.0
1.0
Not
Determ
Total
336
2283
2619
22
29
51
187
2470
2657
1630
31763
33393
20.6
7.2
7.8
1.3
0.1
0.2
11.5
7.8
8.0
100.0
100.0
100.0
2.9
1.0
14.8
1.0
1.5
1.0
Extracted from Midwives’ Notification System on 20 June 2014.
58
Western Australia’s Mothers and Babies 2012, 30th Annual Report
For Aboriginal women, antenatal care in the first trimester was received by the highest
proportion in the Southwest (64.5 per cent) and the Kimberley (45.4 per cent) regions.
For non-Aboriginal women the highest proportions were for residents in the Southwest
(65.7 per cent), the Midwest (58.8 per cent) and South Metropolitan health regions (58.4
per cent) (Table 54).
Table 54: Gestation at first antenatal care visit, Aboriginal status and health
region of residence of women who gave birth in WA, 2012
Aboriginal
Status
Aboriginal
Health
Regions
North Metro
South Metro
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Aboriginal Total
non-Aboriginal North Metro
South Metro
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
non-Aboriginal Total
Grand Total
Gestational Age Groups (weeks)
Did not
Not
1-12
13-24
>24
Attend
Determ
%
%
%
%
%
24.1
29.0
20.6
38.8
45.4
33.9
34.6
64.5
26.3
34.4
55.5
58.4
37.6
51.2
54.3
58.8
48.1
65.7
51.3
56.5
55.4
37.5
39.5
17.6
14.3
29.6
31.1
35.7
24.2
27.5
32.2
33.9
28.1
10.2
13.1
24.6
22.1
37.2
8.6
29.2
28.4
28.6
33.2
25.6
7.8
14.3
11.2
20.3
23.6
3.2
36.3
20.6
8.9
6.3
4.9
3.5
6.9
5.3
10.4
2.0
10.9
7.2
7.8
3.0
1.4
2.9
2.0
0.5
1.7
1.3
1.4
0.0
0.1
0.4
0.2
0.3
0.0
0.1
0.1
2.2
4.5
51.0
30.6
13.3
13.0
6.0
8.1
8.8
11.4
1.7
7.2
47.0
32.0
14.2
13.4
4.3
23.6
8.6
7.8
8.0
Total
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 46 women (2 Aboriginal) where maternal residence was not within WA.
3.4. Previous pregnancies
The proportion of Aboriginal women who gave birth to their first infant (30.5 per cent)
was lower than for non-Aboriginal women (43.5 per cent). Conversely, the proportion of
Aboriginal women who gave birth to their fifth, or higher, child (8.7 per cent) was more
than seven times higher than the proportion for non-Aboriginal women (1.2 per cent)
(Table 55).
Table 55: Number of previous infants and Aboriginal status of women who gave
birth in WA, 2012
Number
Previous Infants
Nil
One or two
Three or four
Five or more
Total
Aboriginal Status of Mother
Aboriginal
non-Aboriginal
No.
%
No.
%
497
30.5
13815
43.5
697
42.8
15588
49.1
294
18.0
1972
6.2
142
8.7
388
1.2
1630
100.0
31763
100.0
Total
No.
%
14312
45.1
16285
51.3
2266
7.1
530
1.7
31734
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Figure 17: Number of previous infants and Aboriginal status of women who gave
birth in WA, 2012
59
Western Australia’s Mothers and Babies 2012, 30th Annual Report
60
49.1
50
Proportion of women
43.5
42.8
40
30.5
30
18.0
20
10
6.2
8.7
1.2
0
No prev infants
1 or 2 prev
3 or 4 prev
5 or more prev
Number of Previous Infants
Aboriginal
non-Aboriginal
For all women who gave birth in 2012 the proportion with a history of caesarean section
was 17.2 per cent. In Aboriginal women, 15.4 per cent had a history of caesarean
section.
The proportion of Aboriginal women with a history of caesarean section followed by a
vaginal birth before they gave birth in 2012 (2.7 per cent) was more than double that of
non-Aboriginal women (0.9 per cent) (Table 56).
Table 56: Previous caesarean section and Aboriginal status of women who gave
birth in WA, 2012
CS in Previous Deliveries
No Previous CS
Previous CS, CS Last Delivery
Previous CS, Vaginal Birth Last Delivery
Total
Aboriginal Status of Mother
Aboriginal
non-Aboriginal
No.
%
No.
%
1379
84.6 26265
82.7
207
12.7
5213
16.4
44
2.7
285
0.9
1630
100.0 31763
100.0
Total
No.
%
27644
82.8
5420
16.2
329
1.0
33393 100.0
Extracted from Midwives’ Notification System on 20 June 2014.
60
Western Australia’s Mothers and Babies 2012, 30th Annual Report
The proportions of Aboriginal women who had given birth previously and had a history
of a stillborn infant (4.1 per cent) or an infant who died following birth (3.9 per cent) or
had either or both (7.5 per cent) were all twice that of non-Aboriginal women (2.2, 1.2
and 3.3 per cent respectively) (Table 57).
Table 57: Number of previous infants who died and Aboriginal status of women
who gave birth in WA, 2012
Stillbirth or Death Previous Deliveries
Previous stillborn infants
None
One or more
Aboriginal Status of Mother
Aboriginal
non-Aboriginal
No.
%
No.
%
Total
No.
%
1087
46
95.9
4.1
17553
395
97.8
2.2
18640
441
97.7
2.3
Previous infants that died
None
One or more
1089
44
96.1
3.9
17737
211
98.8
1.2
18826
255
98.7
1.3
Previous stillbirth or infant that died
None
One or more
Total with previous babies
1048
85
1133
92.5
7.5
100.0
17356
592
17948
96.7
3.3
100.0
18404
677
19081
96.5
3.5
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 14,312 women (497 Aboriginal) without previous infants.
3.5. Smoking tobacco during pregnancy
Smoking tobacco during pregnancy is associated with low birth weight, premature birth,
and perinatal death.
Almost half the Aboriginal women who gave birth in 2012 reported smoking tobacco
during pregnancy (48.2 per cent). This was more than four times the rate of tobacco
smoking for non-Aboriginal women (9.7 per cent) (Table 58).
Table 58: Tobacco smoking and Aboriginal status of women who gave birth in
WA, 2012
Aboriginal status
Aboriginal
Non-Aboriginal
Total
Smoking in pregnancy
Smoking
Non-smoking
No.
%
No.
%
785
48.2
845
51.8
3078
9.7
28685
90.3
3863
11.6
29530
88.4
Total
No.
%
1630
100.0
31763
100.0
33393
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Tobacco smoking for women who gave birth in 2012 varied across regions of residence
and was highest in country areas. For all women who lived in the country areas, there
was a variation in reported rate of tobacco smoking during pregnancy between 14.3 per
cent for Great Southern and 32.9 per cent in the Kimberley. Tobacco smoking during
pregnancy reported by women residing in the metropolitan areas was 7.7 per cent in the
north and 11.6 per cent in the south.
Aboriginal women were more likely to live in the country and were more likely to smoke
tobacco during pregnancy. The highest rates of reported tobacco smoking for Aboriginal
women were 55.0 per cent (Wheatbelt), 54.2 per cent (Midwest),and 51.6 per cent
(Pilbara).
The highest regional reported tobacco smoking rate for non-Aboriginal women was 15.3
per cent in the Goldfields and Wheatbelt (Table 59).
61
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 59: Tobacco smoking, health region of residence and Aboriginal status of
women who gave birth in WA, 2012
Place of residence
Metro
North Metro
South Metro
Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Metro
North Metro
South Metro
Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Maternal Aboriginal Status
Aboriginal
non-Aboriginal
Numbers
278
2232
120
907
158
1325
506
842
39
131
28
89
196
28
96
83
94
72
24
306
44
133
784
3074
Row Percentage
47.6
8.7
51.7
6.9
44.9
10.7
48.5
13.6
38.2
15.3
26.5
13.4
50.0
9.7
54.2
11.6
51.6
10.4
38.7
14.6
55.0
15.3
48.2
9.7
Total
2510
1027
1483
1348
170
117
224
179
166
330
177
3858
9.6
7.7
11.6
18.6
17.7
14.3
32.9
20.1
19.0
15.2
18.6
11.6
Extracted from Midwives’ Notification System on 20 June 2014.
46 women, including 2 who were Aboriginal, were excluded as their residence was not within Western Australia.
Denominators used to calculate Row Percentage in this table are those totals presented in Table 52.
The average number of cigarettes smoked per day reported at two points in pregnancy
indicate that 767 (47.1 per cent) Aboriginal women did not smoke at any time during
pregnancy. Seventy-eight women (4.8 per cent) stopped smoking during pregnancy. Of
all Aboriginal women, 572 (35.1 per cent) were smoking the same number of tobacco
cigarettes before and after 20 weeks gestation of pregnancy. A small proportion, 2.0 per
cent (32 women) increased the average cigarette number they smoked daily (Table 60).
Table 60: Change in tobacco smoking during pregnancy by Aboriginal women
who gave birth in WA, 2012
After 20 weeks
of pregnancy
Not reported
Did not smoke
Occass
<10
10 to 19
20 to 29
30 or more
Total
Average number of cigarettes smoked per day first 20 weeks
of pregnancy
Not
Did not
reported
smoke
Occass <10 10 to 19 20 to 29 ≥ 30
Numbers
76
2
2
5
2
1
767
2
54
19
3
1
19
7
- 333
36
12
3
2
13
162
10
9
1
5
5
64
3
12
78
778
23 410
224
89
28
Total
88
845
20
391
196
78
12
1630
Extracted from Midwives’ Notification System on 20 June 2014.
Green highlight indicates decreased or nil smoking during pregnancy.
Orange highlight indicates no change in smoking during pregnancy.
Red highlight indicates increased smoking during pregnancy.
62
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.6. Complications of Pregnancy
There were nine complications of pregnancy able to be reported for each birth. A tenth
option was “Other” described with free text or ICD-10 Codes. One-third (33.1 per cent)
of all women who gave birth in 2012, had one or more complications during pregnancy.
For Aboriginal women, a higher proportion (39.7 per cent) had one or more
complications during pregnancy compared with non-Aboriginal women. This was a
decrease from the 43.5 per cent proportion for women who gave birth in 2011. (Table
61).
Table 61: Complication of pregnancy, health region of residence and Aboriginal
status of women who gave birth in WA, 2012
Place of residence
Metro
North Metro
South Metro
Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Had one or more complications
Had no complication of pregnancy
Total Women
Aboriginal Status
Aboriginal
non-Aboriginal
No.
%
No.
%
209
12.8
8365
26.4
80
4.9
4479
14.1
129
7.9
3886
12.3
437
26.8
2023
6.4
61
3.7
344
1.1
21
1.3
256
0.8
168
10.3
79
0.2
64
3.9
244
0.8
67
4.1
202
0.6
23
1.4
651
2.1
33
2.0
247
0.8
646
39.7
10388
32.8
982
1628
Total
No.
8574
4559
4015
2460
405
277
247
308
269
674
280
11034
%
25.7
13.7
12.0
7.4
1.2
0.8
0.7
0.9
0.8
2.0
0.8
33.1
60.3
21331
67.2
22313
66.9
100.0
31719
100.0
33347
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
46 women, including 2 who were Aboriginal, were excluded as their residence was not within Western Australia.
63
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Of complications of pregnancy reported, all except threatened miscarriage was in a
higher proportion of Aboriginal women than in non-Aboriginal women. The proportion of
Aboriginal women with urinary tract infection was almost three times that in nonAboriginal women. In Aboriginal women there were similar proportions to non-Aboriginal
women experiencing antepartum haemorrhage (Table 62).
Table 62: Complications of pregnancy and Aboriginal status of women who gave
birth in WA, 2012
Complications of Pregnancy1
Threatened miscarriage
Threatened preterm labour
Urinary tract infection
Pre-eclampsia
Antepartum haemorrhage
— placenta praevia
— abruption
— other
Prelabour rupture of membranes
Gestational diabetes
Other
One or more complications
No complications of pregnancy
Total Women
Aboriginal Status
Aboriginal
non-Aboriginal
No.
%
No.
%
7
0.4
907
2.9
74
4.5
691
2.2
148
9.1
994
3.1
49
3.0
733
2.3
5
7
42
78
120
337
648
982
1630
0.3
0.4
2.6
4.8
7.4
20.7
39.8
60.2
100.0
134
86
762
1105
2231
5145
10409
21354
31763
0.4
0.3
2.4
3.5
7.0
16.2
32.8
67.2
100.0
Total
No.
914
765
1142
782
%
2.7
2.3
3.4
2.3
139
93
804
1183
2351
5482
11057
22336
33393
0.4
0.3
2.4
3.5
7.0
16.4
33.1
66.9
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
1
A woman may have more than one complication during pregnancy
64
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.7. Medical conditions before pregnancy
There were four pre-existing medical conditions able to be reported for each woman
that gave birth. A fifth option was “Other” described with text or ICD-10 Codes. More
than one-third (40.8 per cent) of all women who gave birth in 2012, had one or more
pre-existing medical conditions. For Aboriginal women, the proportion (49.1 per cent)
was higher than for non-Aboriginal women (40.4 per cent) (Table 63).
In 2012, the proportion of Aboriginal women with pre-existing diabetes (2.3 per cent)
was three times the proportion of non-Aboriginal women with the same condition (0.7
per cent). A higher proportion of Aboriginal women had “Other” medical conditions
reported than non-Aboriginal women did, 43.2 per cent and 31.9 percent respectively.
For all other specified conditions, a lower proportion of Aboriginal women than nonAboriginal women were affected (Table 63).
Table 63: Pre-existing medical conditions and Aboriginal status of women who
gave birth in WA, 2012
Medical Conditions before
Pregnancy1
Essential hypertension
Pre-existing diabetes
Asthma
Genital herpes
Other
One or more conditions
No medical conditions
Total Women
Aboriginal Status
Aboriginal
non-Aboriginal
No.
%
No.
%
18
1.1
340
1.1
38
2.3
223
0.7
154
9.4
3206
10.1
15
0.9
621
2.0
704
43.2
10125
31.9
800
49.1
12833
40.4
830
50.9
18930
59.6
1630
100.0
31763
100.0
Total
No.
358
261
3360
636
10829
13633
19760
33393
%
1.1
0.8
10.1
1.9
32.4
40.8
59.2
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
1
A woman may have more than one pre-existing medical condition
65
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.8. Procedures and treatments
There were seven procedures and treatments able to be reported for each woman who
gave birth. Of all women who gave birth in 2012, 96.7 per cent had one or more of the
listed procedures and treatments. For Aboriginal women, the proportion (97.7 per cent)
was similar to non-Aboriginal women (96.7 per cent) (Table 64).
The proportion of Aboriginal women who an antenatal (33.6 per cent) or intrapartum
cardiotocograph (57.6 per cent) was higher than for non-Aboriginal women, 23.7 and
55.0 per cent respectively. A slightly higher proportion of Aboriginal women had cervical
suture or Ultrasound. For all other specified procedures and treatment, a lower
proportion of Aboriginal women than non-Aboriginal women received the procedure or
treatment (Table 64).
Table 64: Procedures, treatments and Aboriginal status of women who gave birth
in WA, 2012
Procedures and Treatments1
Fertility treatments
Cervical suture
CVS (placental biopsy)
Amniocentesis
Ultrasound
CTG antepartum
CTG intrapartum
One or more procedures
No procedures
Total Women
Aboriginal Status
Aboriginal
non-Aboriginal
No.
%
No.
%
***
1131
3.6
4-9
93
0.3
140
0.4
13
0.8
768
2.4
1545
94.8
29891
94.1
548
33.6
7542
23.7
939
57.6
17484
55.0
1593
97.7
30713
96.7
37
2.3
1050
3.3
1630
100.0
31763
100.0
Total
No.
%
1130-33
3.4
101
0.3
140
0.4
781
2.3
31436
94.1
8090
24.2
18423
55.2
32306
96.7
1087
3.3
33393
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
1
A woman may have more than one treatment or procedure during the pregnancy
66
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.9. Labour and birth details
3.9.1.
Onset of labour
Labour established spontaneously for 62.9 per cent of Aboriginal women who gave birth
in WA in 2012. This was a higher proportion than for non-Aboriginal women (49.4 per
cent).
Labour was induced for 24.7 per cent of Aboriginal women.
A lower proportion of Aboriginal women (12.4 per cent) than non-Aboriginal women
(21.3 per cent) gave birth by caesarean section without experiencing labour (Table 65).
Table 65: Onset of labour and Aboriginal status of women who gave birth in WA,
2012
Onset of labour
Spontaneous not Augmented
Spontaneous and Augmented
Induced
No labour
Total
Aboriginal Status
Aboriginal
non-Aboriginal
No.
%
No.
%
733
45.0
9827
30.9
292
17.9
5865
18.5
403
24.7
9317
29.3
202
12.4
6754
21.3
1630
100.0 31763
100.0
Total
No.
%
10560
31.6
6157
18.4
9720
29.1
6956
20.8
33393
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
3.9.2.
Place of birth
The place of birth of the largest proportion of Aboriginal women was at the tertiary
maternity hospital (26.1 per cent) and 21.3 per cent gave birth in health services in the
Kimberley. Twice the proportion of Aboriginal women gave birth in the southern (13.5
per cent) than in the northern metropolitan area (6.0 per cent). Most Aboriginal women
gave birth in public hospitals (98.0 per cent). They did not give birth at home nor in
designated birth centres (Table 66).
Table 66: Place of birth and Aboriginal status of women who gave birth in WA,
2012
Place of birth
Private Homebirth
Metro
Private Metro
Private site with Public
Public Homebirth
Birth Centres
Tertiary
North Metro
South Metro
Country
Private Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Aboriginal status
Aboriginal
non-Aboriginal
Number
56
Total
56
7
31
425
97
220
8785
4030
153
325
5185
2718
5714
8792
4061
153
325
5610
2815
5934
***
86
41
348
133
162
56
22
1629-32
839
781
523
240
399
454
1376
185
31763
840-843
867
564
588
532
616
1432
207
33393
67
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Place of birth
Private Homebirth
Metro
Private Metro
Private site with Public
Public Homebirth
Birth Centres
Tertiary
North Metro
South Metro
Country
Private Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Private Homebirth
Metro
Private Metro
Private site with Public
Public Homebirth
Birth Centres
Tertiary
North Metro
South Metro
Country
Private Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Aboriginal status
Aboriginal
non-Aboriginal
Row Percentage
100.0
0.1
0.8
7.6
3.4
3.7
Total
100.0
99.9
99.2
100.0
100.0
92.4
96.6
96.3
100.0
100.0
100.0
100.0
100.0
100.0
100.0
99.8
90.1
92.7
40.8
75.0
73.7
96.1
89.4
95.1
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
0.2
0.2
0.4
1.9
26.1
6.0
13.5
27.7
12.7
0.5
1.0
16.3
8.6
18.0
26.3
12.2
0.5
1.0
16.8
8.4
17.8
***
5.3
2.5
21.3
8.2
9.9
3.4
1.3
100.0
2.6
2.5
1.6
0.8
1.3
1.4
4.3
0.6
100.0
2.5
2.6
1.7
1.8
1.6
1.8
4.3
0.6
100.0
***
9.9
7.3
59.2
25.0
26.3
3.9
10.6
4.9
Column Percentage
-
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
68
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.9.3.
Method of birth
A higher proportion of Aboriginal women had spontaneous vertex (66.6 per cent) and
breech births (1.2 per cent) than did non-Aboriginal women (50.2 and 0.4 per cent
respectively). Aboriginal women had a lower caesarean section rate (25.7 per cent)
when compared to the rate for non-Aboriginal women (34.4 per cent) with elective
caesarean proportion in non-Aboriginal women (17.7 per cent) more than twice that of
Aboriginal women (8.5 per cent). Proportions of instrumental vaginal births in Aboriginal
women (4.7 and 1.8 per cent) were less than those for non-Aboriginal women (12.4 and
2.6 per cent respectively) (Table 67).
Table 67: Method of birth and Aboriginal status for women who gave birth in WA,
2012
Method of birth of first infant
Spontaneous
Breech
Vacuum
Forceps
Elective Caesarean
Emergency Caesarean
Total
Aboriginal status
Aboriginal
non-Aboriginal
No.
%
No.
%
1086
66.6
15594
50.2
19
1.2
113
0.4
77
4.7
4003
12.4
29
1.8
931
2.6
138
8.5
5831
17.7
281
17.2
5291
16.7
1630 100.0
31763
100.0
Total
No.
%
16680
50.0
132
0.4
4080
12.2
960
2.9
5969
17.9
5572
16.7
33393
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Method of birth reported is that for the only or first infant of the pregnancy.
3.9.4.
Complications of labour or birth
The differences in proportion of complications of labour or birth (Table 68) between
Aboriginal and non-Aboriginal women may be partly explained by the differences seen
by method of birth in Table 67.
There were a higher proportion of Aboriginal women who had complications related to
vaginal birth, for example precipitate delivery, cord tight around neck, manual removal
of placenta and persistent occipito posterior position.
Aboriginal women had a higher primary postpartum haemorrhage rate (23.9 per cent)
compared with non-Aboriginal women (19.0 per cent). However, a slightly lower
proportion of Aboriginal women had delayed progress in labour or cephalopelvic
disproportion. A higher proportion of non-Aboriginal women (37.0 per cent) had “Other”
complications of labour than non-Aboriginal women (33.4 per cent). Overall, a higher
proportion of Aboriginal women had complications (67.8 per cent) than did nonAboriginal women (61.9 per cent).
69
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 68: Complications of labour or birth and Aboriginal status of women who
gave birth in WA, 2012
Complications of labour or birth1
Precipitate delivery
Fetal compromise
Prolapsed cord
Cord tight around neck
Cephalopelvic disproportion
Primary Postpartum Haemorrhage (PPH)
Retained placenta manual removal
Persistent occipito posterior
Shoulder dystocia
Failure to progress <=3cms
Failure to progress >3cms
Previous caesarean section
Other
One or more complications
No complications
Aboriginal status
Aboriginal
non-Aboriginal
No.
%
No.
%
159
9.8
1094
3.4
205
12.6
3181
10.0
6
0.4
42
0.1
37
2.3
549
1.7
8
0.5
255
0.8
390
23.9
6049
19.0
35
2.1
305
1.0
35
2.1
547
1.7
29
1.8
468
1.5
95
5.8
2080
6.5
67
4.1
1537
4.8
244
15.0
5481
17.3
603
37.0
10594
33.4
1105
67.8
19665
61.9
525
32.2
12098
38.1
Total
No.
%
1253
3.8
3386
10.1
48
0.1
586
1.8
263
0.8
6439
19.3
340
1.0
582
1.7
497
1.5
2175
6.5
1604
4.8
5725
17.1
11197
33.5
20770
62.2
12623
37.8
Total Women
1630
33393
100.0
31763
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
These data include reasons for caesarean section of the first or only infant born from the pregnancy.
1
A woman may have had more than one pre-existing medical condition
70
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.10. Trauma to perineum and/or vagina
Among the 1,211 Aboriginal women who gave birth vaginally in 2012, almost twice as
many as non-Aboriginal women had an intact perineum following birth, 63.3 per cent
compared to 34.3 per cent.
When comparing any type of perineal trauma, a lower proportion of Aboriginal women
than non-Aboriginal women experienced the trauma (Table 69).
Table 69: Perineal status and Aboriginal status for women who gave birth
vaginally in WA, 2012
Perineal Status
Intact
st
1 degree tear/vaginal tear
nd
2 degree tear
rd
3 degree tear
Episiotomy
Episiotomy plus tear
th
4 degree tear
Other
Total Women
Aboriginal Status
Aboriginal
Non-Aboriginal
No.
%
No.
%
766
63.3
7078
34.3
166
13.7
3064
14.9
151
12.5
5170
25.1
16
1.3
445
2.2
81
6.7
3538
17.2
19
1.6
870
4.2
***
***
38
0.2
11
0.9
424
2.1
1208-12
100.0
20627
100.0
Total
No.
%
7844
35.9
3230
14.8
5321
24.4
461
2.1
3619
16.6
889
4.1
35-39
0.2
435
2.0
21838
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Table excludes 14 cases where perineal status was not reported.
Where an Episiotomy extended to a 1st or 2nd degree tear, these cases were included in item “Episiotomy plus tear”. Where an
Episiotomy extended to a 3rd or 4th degree tear, these cases were included in the relevant item “3rd degree tear” or “4th degree tear”.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
71
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.11. Infants born to Aboriginal women
In 2012, there were 1,657 infants born to Aboriginal mothers. 98.3 per cent of these
infants were born alive.
The proportion of infants born to Aboriginal women who were stillborn (1.7 per cent)
was almost three times the proportion of infants of non-Aboriginal women who were
stillborn (0.6 per cent) (Table 70).
The proportion of stillborn infants where time of fetal death was not specified were
similar in both Aboriginal and non-Aboriginal women.
For almost three-fifths of the stillborn infants (59.1 per cent), death occurred before the
onset of labour. For infants of Aboriginal women, the proportion of stillborn infants that
died before onset of labour was 75.0 per cent, higher than the non-Aboriginal proportion
of 56.9 per cent.
Conversely, the proportion of stillborn infants born to Aboriginal women where death
occurred during labour (17.9 per cent) was half the proportion of stillborn infants born to
non-Aboriginal women (34.9 per cent).
Table 70: Birth status and maternal Aboriginal status for infants born in WA, 2012
Birth Status
Liveborn
Stillborn
Total
Time of death
Antenatal
Intrapartum
Unspecified time
Total
Maternal Aboriginal Status
Aboriginal
non-Aboriginal
No.
%
No.
%
1629
98.3
31996
99.4
28
1.7
209
0.6
1657 100.0
32205 100.0
21
5
2
28
75.0
17.9
7.1
100.0
119
73
17
209
56.9
34.9
8.1
100.0
Total
No.
%
33625
99.3
237
0.7
33862 100.0
140
78
19
237
59.1
32.9
8.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Births of infants reported by public establishments are never reported as unspecified time of death. For these cases, unknown time
of fetal death was reported as an antenatal death.
Non-Aboriginal women living in the north metropolitan area comprised the highest
proportion of infants born in WA (41.2 per cent). Aboriginal women living in the
Kimberley had the highest proportion of Aboriginal infants born (24.1 per cent).
Aboriginal women living in the south metropolitan area had the highest proportion of
stillborn infants (2.2 per cent). The next highest proportion was for Aboriginal women
living in the Goldfields or Great Southern (2.0 per cent). Residents of the Wheatbelt had
the highest proportion of stillborn infants born to non-Aboriginal women (1.0 per cent)
(Table 71).
72
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 71: Birth status, maternal residence and maternal Aboriginal status for
infants born in WA, 2012
Health Region
maternal residence
Maternal Aboriginal Status
non-Aboriginal
Total
Livebirth Stillbirth
Number
***
***
13180
77
8
357
12535
92
***
***
864
***
***
***
671
6
6
399
296
***
***
***
719
***
***
***
697
5
65
2114
10
***
***
877
9
26
1655
31953
207
Row Percentage
1.3
100.0
99.4
0.6
2.2
100.0
99.3
0.7
2.0
100.0
99.5
0.5
2.0
100.0
99.1
0.9
1.5
100.0
99.7
0.3
1.7
100.0
99.6
0.4
1.1
100.0
99.3
0.7
100.0
99.5
0.5
1.2
100.0
99.0
1.0
1.6
100.0
99.4
0.6
Column Percentage
11.5
14.3
41.2
37.2
30.8
21.6
39.2
44.4
7.7
6.2
2.7
1.9
3.8
3.0
2.1
2.9
23.1
24.1
0.9
0.5
11.5
10.9
2.3
1.4
7.7
11.1
2.2
2.4
0.0
3.9
6.6
4.8
3.8
5.0
2.7
4.3
100.0
100.0
100.0
100.0
Aboriginal
Livebirth Stillbirth
North Metropolitan
South Metropolitan
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
South West
Wheatbelt
Total
233
349
100
49
393
177
182
65
81
1629
North Metropolitan
South Metropolitan
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
South West
Wheatbelt
Total
98.7
97.8
98.0
98.0
98.5
98.3
98.9
100.0
98.8
98.4
North Metropolitan
South Metropolitan
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
South West
Wheatbelt
Total
14.3
21.4
6.1
3.0
24.1
10.9
11.2
4.0
5.0
100.0
Total
Total
13257
12627
***
677
***
***
702
2124
886
32160
13493
12984
970
727
696
902
886
2189
968
33815
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
41.2
39.3
2.7
2.1
0.9
2.2
2.2
6.6
2.8
100.0
39.9
38.4
2.9
2.1
2.1
2.7
2.6
6.5
2.9
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 47 infants (4 stillborn) where mother was not resident in WA.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
73
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.11.1. Crude birth rate
Notification forms (sample on Page 121) were received for 1,657 infants born in 2012 to
Aboriginal mothers in WA. This was a decrease of 83 (4.8 per cent) infants from the
1,740 infants born in 2011. Of the infants born in 2012, 98.3 per cent were born alive.
The crude birth rate for infants of Aboriginal women in WA in 2012 was 21.1. This rate
was the lowest reported rate for data available since 1983 (Table 72).
Table 72: Trends for crude birth rate and maternal Aboriginal status for infants
born in WA, 1983-2012
Birth Status
Livebirth
Stillbirth
Year
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
No.
1135
1179
1235
1231
1329
1428
1431
1542
1464
1412
1436
1431
1444
1426
1549
1506
1603
1587
1632
1646
1525
1559
1697
1780
1810
1715
1740
1677
1706
1629
%
98.6
98.0
98.4
98.4
98.6
98.6
98.4
98.9
98.5
98.5
98.6
98.4
98.6
98.6
97.9
99.0
98.6
98.3
98.9
98.4
98.4
98.9
98.6
98.5
99.0
98.7
98.7
98.6
98.0
98.3
No.
16
24
20
20
19
21
23
17
22
22
20
24
20
20
33
15
22
27
18
27
25
17
24
27
19
23
23
23
34
28
%
1.4
2.0
1.6
1.6
1.4
1.4
1.6
1.1
1.5
1.5
1.4
1.6
1.4
1.4
2.1
1.0
1.4
1.7
1.1
1.6
1.6
1.1
1.4
1.5
1.0
1.3
1.3
1.4
2.0
1.7
Total
No.
1151
1203
1255
1251
1348
1449
1454
1559
1486
1434
1456
1455
1464
1446
1582
1521
1625
1614
1650
1673
1550
1576
1721
1807
1829
1738
1763
1700
1740
1657
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Aboriginal
1
Population
41,011
42,259
43,491
44,760
46,098
47,461
48,878
50,306
51,834
53,263
54,650
56,072
57,511
59,001
60,369
61,712
63,199
64,557
65,923
66,781
67,754
68,635
69,608
70,813
71,826
72,885
73,820
75,037
76,096
77,119
Crude Birth
2
Rate
28.1
28.5
28.9
27.9
29.2
31.0
28.7
26.9
26.6
25.9
25.5
24.5
26.2
24.6
25.7
25.0
25.0
25.1
22.9
23.0
24.7
25.5
25.5
23.8
23.9
22.7
22.9
26.9
26.6
21.1
Data Extracted from Midwives’ Notification System on 20 June 2014.
Trend table begins in 1983 as population date not available for 1980 to 1982.
1
Source of population data: ABS Estimated Resident Populations for WA.
2
Crude birth rate was determined by the calculation: 1000 times Total infants born alive divided by midyear Total Population for the geographical area.
74
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.11.2. Birthweight and gestational age
Preterm birth (less than 37 weeks gestation) is associated with significant morbidity and
mortality in newborn infants.
In 2012, preterm birth occurred for 18.4 per cent of all infants born to Aboriginal women.
Similarly low birthweight (less than 2500 grams) occurred in 15.7 per cent of these
infants (Table 73).
Table 73: Gestational age and birthweight for infants born to Aboriginal mothers
in WA, 2012
Birthweight
(grams)
Gestation (weeks)
20-27
< 1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
>= 4500
Total
84.4
9.1
11.5
1.8
< 1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
>= 4500
Total
90.0
10.0
100.0
100.0
28-32
33-36
Row Percentage
15.6
90.9
38.2
45.5
1.4
60.7
22.3
42.3
0.3
18.9
4.3
3.4
1.0
3.6
13.0
Column Percentage
8.5
50.8
35.6
11.6
3.4
39.4
98.3
50.9
1.7
31.9
11.1
5.6
0.5
100.0
100.0
37-44
Total
16.4
37.9
23.8
80.8
95.7
96.6
99.0
100.0
81.6
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
0.7
3.9
4.6
21.8
39.9
25.1
7.0
1.6
100.0
1.9
2.0
3.3
8.4
15.7
22.0
34.0
21.2
5.8
1.3
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
75
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.11.3. Birthweight
In infants of Aboriginal mothers, the proportion of infants with low birthweight (less than
2,500 grams) was greater (15.7 per cent) than in infants born to non-Aboriginal mothers
(6.2 per cent).
Infants of Aboriginal mothers had a similar proportion to those of non-Aboriginal
mothers with birthweight of 4,500 grams or more. (Table 74).
Table 74: Birthweight and maternal Aboriginal status for infants born in WA, 2012
Birthweight
(grams)
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
≥ 4500
Total
Aboriginal Status of Mother
Aboriginal
non-Aboriginal
No.
%
No.
%
32
1.9
252
0.8
33
2.0
163
0.5
55
3.3
355
1.1
140
8.4
1216
3.8
260
15.7
1986
6.2
365
22.0
4971
15.4
563
34.0 12044
37.4
352
21.2
9894
30.7
96
5.8
2863
8.9
21
1.3
444
1.4
1657
100.0 32202
100.0
Total
No.
284
196
410
1356
2246
5336
12607
10246
2959
465
33859
%
0.8
0.6
1.2
4.0
6.6
15.8
37.2
30.3
8.7
1.4
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
3 cases excluded as no birthweight reported
All Infants: Mean = 3335.7 grams. Standard deviation = 601.1 grams. Median = 3380 grams.
Infants of Aboriginal mothers: Mean = 3093.0 grams. Standard deviation = 729.8 grams. Median = 3185 grams.
Infants of non-Aboriginal mothers: Mean = 3348.2 grams. Standard deviation = 591.0 grams. Median = 3390 grams.
76
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Trend data indicates that the annual proportion of infants born to Aboriginal mothers
with low birthweight ranged between 11.0 per cent in 1987 and 16.5 per cent in 2005
(Table 75).
In 2012 the proportion of 15.7 per cent was the second highest proportion in data
available.
The proportion of infants with low birthweight born to non-Aboriginal women was 6.2
percent in 2012 with little change since 1980.
Table 75: Trends for birthweight and maternal Aboriginal status for infants born
in WA, 1980-2012
Aboriginal Status of Mother
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
< 1500 grams
No.
%
15
1.4
24
2.1
35
3.1
22
1.9
43
3.6
47
3.7
32
2.6
31
2.3
44
3.0
40
2.8
34
2.2
48
3.2
33
2.3
62
4.3
47
3.2
41
2.8
39
2.7
45
2.8
44
2.9
63
3.9
62
3.8
59
3.6
55
3.3
57
3.7
54
3.4
64
3.7
71
3.9
50
2.7
60
3.5
62
3.5
56
3.3
57
3.3
65
3.9
Aboriginal
< 2500 grams
No.
%
133
12.8
146
13.1
150
13.3
153
13.3
166
13.8
176
14.0
151
12.1
148
11.0
197
13.6
163
11.2
177
11.4
220
14.8
169
11.8
191
13.1
206
14.2
176
12.0
198
13.7
217
13.7
192
12.6
233
14.3
232
14.4
259
15.7
238
14.2
235
15.2
235
14.9
284
16.5
269
14.9
300
16.4
278
16.0
256
14.5
238
14.0
245
14.1
260
15.7
≥ 2500 grams
No.
%
905
87.2
972
86.9
982
86.7
998
86.7
1037
86.2
1079
86.0
1099
87.9
1200
89.0
1252
86.4
1291
88.8
1382
88.6
1266
85.2
1265
88.2
1265
86.9
1249
85.8
1288
88.0
1247
86.3
1365
86.3
1329
87.4
1392
85.7
1382
85.6
1391
84.3
1435
85.8
1315
84.8
1340
85.1
1437
83.5
1538
85.1
1529
83.6
1460
84.0
1507
85.5
1462
86.0
1495
85.9
1397
84.3
non-Aboriginal
< 1500 grams
< 2500 grams
No.
%
No.
%
265
1.3 1116
5.6
239
1.1 1175
5.6
251
1.2 1197
5.6
299
1.4 1355
6.2
271
1.2 1264
5.8
318
1.4 1351
6.1
305
1.3 1329
5.9
311
1.4 1405
6.1
340
1.4 1420
6.0
356
1.5 1573
6.5
280
1.1 1457
6.0
311
1.3 1405
6.0
309
1.3 1481
6.2
281
1.2 1456
6.1
348
1.5 1441
6.0
322
1.3 1496
6.2
349
1.4 1542
6.4
328
1.4 1467
6.2
320
1.3 1538
6.4
314
1.3 1488
6.2
337
1.4 1521
6.4
325
1.4 1498
6.4
297
1.3 1431
6.2
286
1.2 1477
6.4
357
1.5 1586
6.6
357
1.4 1631
6.5
381
1.4 1726
6.4
381
1.3 1757
6.2
398
1.4 1775
6.1
442
1.5 1853
6.3
389
1.3 1825
6.2
414
1.4 1897
6.2
415
1.3 1986
6.2
≥ 2500 grams
No.
%
18651
94.4
19928
94.4
20062
94.4
20566
93.8
20496
94.2
20751
93.9
21308
94.1
21453
93.9
22289
94.0
22516
93.5
23003
94.0
22117
94.0
22408
93.8
22424
93.9
22529
94.0
22486
93.8
22597
93.6
22217
93.8
22619
93.6
22657
93.8
22093
93.6
21793
93.6
21680
93.8
21650
93.6
22370
93.4
23626
93.5
25133
93.6
26487
93.8
27155
93.9
27591
93.7
27732
93.8
28554
93.8
30216
93.8
Extracted from Midwives’ Notification System on 20 June 2014.
77
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.11.4. Risk of Low Birthweight
Since 1980, infants born to Aboriginal mothers had a higher risk (RR 2.5) of low
birthweight than infants of non-Aboriginal women. In 2012, the RR for infants of
Aboriginal mothers to weigh less than 1500 grams was 3.0 times that for infants of nonAboriginal mothers (Table 76).
Table 76: Trends for Relative Risk of low birthweight and maternal Aboriginal
status for infants born in WA, 1980-2012
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Proportion in Birthweight Group
Non-Aboriginal
Aboriginal
<1500
<2500
>=2500
<1500
<2500
>=2500
1.3
5.6
94.4
1.4
12.8
87.2
1.1
5.6
94.4
2.1
13.1
86.9
1.2
5.6
94.4
3.1
13.3
86.7
1.4
6.2
93.8
1.9
13.3
86.7
1.2
5.8
94.2
3.6
13.8
86.2
1.4
6.1
93.9
3.7
14.0
86.0
1.3
5.9
94.1
2.6
12.1
87.9
1.4
6.1
93.9
2.3
11.0
89.0
1.4
6.0
94.0
3.0
13.6
86.4
1.5
6.5
93.5
2.8
11.2
88.8
1.1
6.0
94.0
2.2
11.4
88.6
1.3
6.0
94.0
3.2
14.8
85.2
1.3
6.2
93.8
2.3
11.8
88.2
1.2
6.1
93.9
4.3
13.1
86.9
1.5
6.0
94.0
3.2
14.2
85.8
1.3
6.2
93.8
2.8
12.0
88.0
1.4
6.4
93.6
2.7
13.7
86.3
1.4
6.2
93.8
2.8
13.7
86.3
1.3
6.4
93.6
2.9
12.6
87.4
1.3
6.2
93.8
3.9
14.3
85.7
1.4
6.4
93.6
3.8
14.4
85.6
1.4
6.4
93.6
3.6
15.7
84.3
1.3
6.2
93.8
3.3
14.2
85.8
1.2
6.4
93.6
3.7
15.2
84.8
1.5
6.6
93.4
3.4
14.9
85.1
1.4
6.5
93.5
3.7
16.5
83.5
1.4
6.4
93.6
3.9
14.9
85.1
1.3
6.2
93.8
2.7
16.4
83.6
1.4
6.1
93.9
3.5
16.0
84.0
1.5
6.3
93.7
3.5
14.5
85.5
1.3
6.2
93.8
3.3
14.0
86.0
1.4
6.2
93.8
3.3
14.1
85.9
1.3
6.2
93.8
3.9
15.7
84.3
Aboriginal Relative Risk
<1500
<2500
>=2500
1.1
2.3
0.9
1.9
2.3
0.9
2.6
2.4
0.9
1.4
2.1
0.9
3.0
2.4
0.9
2.6
2.3
0.9
2.0
2.1
0.9
1.6
1.8
0.9
2.1
2.3
0.9
1.9
1.7
0.9
2.0
1.9
0.9
2.5
2.5
0.9
1.8
1.9
0.9
3.6
2.1
0.9
2.1
2.4
0.9
2.2
1.9
0.9
1.9
2.1
0.9
2.0
2.2
0.9
2.2
2.0
0.9
3.0
2.3
0.9
2.7
2.3
0.9
2.6
2.5
0.9
2.5
2.3
0.9
3.1
2.4
0.9
2.3
2.3
0.9
2.6
2.5
0.9
2.8
2.3
0.9
2.1
2.6
0.9
2.5
2.6
0.9
2.3
2.3
0.9
2.5
2.3
0.9
2.4
2.3
0.9
3.0
2.5
0.9
Extracted from Midwives’ Notification System on 20 June 2014.
78
Western Australia’s Mothers and Babies 2012, 30th Annual Report
When excluding stillborn infants, the proportion of infants with low birthweight remained
higher for those of Aboriginal women (14.5 per cent) than infants born to mothers that
were not Aboriginal (5.6 per cent) (Table 77).
Table 77: Birthweight and maternal Aboriginal status for infants born alive in WA,
2012
Birthweight
(grams)
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
≥ 4500
Total
Aboriginal Status of Mother
Aboriginal
non-Aboriginal
No.
%
No.
%
15
0.9
107
0.3
28
1.7
157
0.5
53
3.3
337
1.1
140
8.6
1203
3.8
236
14.5
1804
5.6
362
22.2
4962
15.5
562
34.5
12035
37.6
352
21.6
9889
30.9
96
5.9
2861
8.9
21
1.3
444
1.4
1629 100.0
31995
100.0
Total
No.
%
122
0.4
185
0.6
390
1.2
1343
4.0
2040
6.1
5324
15.8
12597
37.5
10241
30.5
2957
8.8
465
1.4
33624
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 1 liveborn infant where birthweight not reported
All Liveborn Infants: Mean = 3351.9 grams. Standard deviation = 565.1 grams. Median = 3390 grams.
Liveborn infants of Aboriginal mothers: Mean = 3128.2 grams. Standard deviation = 675.3 grams. Median = 3200 grams.
Liveborn infants of non-Aboriginal mothers: Mean = 3363.3 grams. Standard deviation = 556.5 grams. Median = 3390 grams.
3.11.5. Low birthweight and place of residence
For infants born alive to Aboriginal women, the proportion of those living in metropolitan
areas that had low birthweight was 14.4 per cent compared with 14.5 per cent of those
living in country areas. Proportions were more than double those occurring in infants
born alive to non-Aboriginal women, 5.8 per cent and 5.0 per cent respectively. (Table
78).
Table 78: Low birthweight, maternal residence and maternal Aboriginal status for
infants born alive in WA, 2012
Health Region of Maternal Residence
Metro
North Metro
South Metro
Country
Goldfields
Great Southern
Kimberley
Midwest
Pilbara
Southwest
Wheatbelt
Total
Aboriginal Status
Aboriginal
non-Aboriginal
Low
Low
Birthwt
Total
%
Birthwt
Total
%
84
582
14.4
1487 25715
5.8
38
233
16.3
768 13180
5.8
46
349
13.2
719 12535
5.7
152
1047
14.5
312
6238
5.0
19
100
19.0
50
864
5.8
7
49
14.3
46
671
6.9
53
393
13.5
10
296
3.4
31
177
17.5
29
719
4.0
21
182
11.5
20
697
2.9
8
65
12.3
108
2114
5.1
13
81
16.0
49
877
5.6
236
1629
14.5
1799 31953
5.6
Extracted from Midwives’ Notification System on 20 June 2014.
Infants included in Low Birthweight Number had a birthweight less than 2500 grams.
43 liveborn infants, including 5 that were low birthweight were excluded as their residence was not within Western Australia.
79
Western Australia’s Mothers and Babies 2012, 30th Annual Report
3.12. Aboriginal status of infant
From January 2012, midwives commenced reporting the data item “Indigenous Status
of Infant” as defined by the Australian Institute of Health and Welfare.
Of the 1,657 infants born to Aboriginal mothers, 89.5 per cent were reported as
Aboriginal, 1.2 per cent as Aboriginal and Torres Strait Islander and 0.3 were Torres
Strait Islander and not Aboriginal. A small proportion of these infants (8.4 per cent) were
reported as other than Aboriginal or Torres Strait Islander.
As well as infants of Aboriginal mothers, an additional 190 infants were identified as
Aboriginal and/or Torres Strait Islander using the “Indigenous Status” of Infant data.
Table 79: Infant Aboriginal status and maternal Aboriginal status for infants born
in WA, 2012
Aboriginal Status of Infant
Aboriginal Status of Mother
Aboriginal
No.
%
Non-Aboriginal
No.
%
Total
No.
%
Aboriginal not Torres Strait Islander
Torres Strait Islander not Aboriginal
Aboriginal and Torres Strait Islander
Other
Not specified
1483
5
20
140
9
89.5
0.3
1.2
8.4
0.5
183
***
***
31752
263
0.6
0.0
0.0
98.6
0.8
1666
***
***
31892
272
4.9
0.0
0.1
94.2
0.8
Total
1657
100.0
31942
100.0
33590
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
80
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4. Infants
4.1. Metrics of infants born
Notification forms (sample on Page 121) were received for 33,862 infants born in 2012.
This was an increase of 1,671 (5.2 per cent) infants from the 32,191 infants born in
2011. Of the infants born in 2012, 99.3 per cent were born alive (Table 80).
4.1.1.
Crude birth rate
Trend data indicate that the crude birth rate generally declined from a high of 17.0 in
1981 to a low of 12.5 per 1000 total population in 2003. An increase to 14.2 occurred in
2007. Since 2007, the rate varied little and was 13.8 per 1000 in 2012 (Table 80 and
Figure 18).
Table 80: Trends for birth status and crude birth rate for infants born in WA, 19802012
Condition at Birth
Live Birth
Stillbirth
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
No.
20636
22039
22196
22875
22795
23153
23703
24015
24981
25359
25844
24814
25158
25160
25237
25255
25386
25095
25514
25591
25022
24774
24609
24493
25341
26778
28456
29884
30443
30973
31039
31922
33625
%
99.1
99.2
99.1
99.1
99.3
99.1
99.2
99.2
99.3
99.3
99.3
99.2
99.3
99.3
99.3
99.2
99.2
99.3
99.4
99.3
99.2
99.3
99.3
99.3
99.3
99.3
99.3
99.4
99.3
99.3
99.3
99.2
99.3
No.
178
182
195
197
168
204
185
191
177
184
175
194
165
176
188
191
199
171
164
179
206
167
175
184
188
200
209
189
225
234
218
269
237
%
0.9
0.8
0.9
0.9
0.7
0.9
0.8
0.8
0.7
0.7
0.7
0.8
0.7
0.7
0.7
0.8
0.8
0.7
0.6
0.7
0.8
0.7
0.7
0.7
0.7
0.7
0.7
0.6
0.7
0.7
0.7
0.8
0.7
Total
No.
20814
22221
22391
23072
22963
23357
23888
24206
25158
25543
26019
25008
25323
25336
25425
25446
25585
25266
25678
25770
25228
24941
24784
24677
25529
26978
28665
30073
30668
31207
31257
32191
33862
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Total
1
Population
1269068
1300056
1338899
1369318
1391539
1419012
1459247
1496472
1535449
1578761
1613447
1636599
1658609
1678292
1703503
1734228
1765635
1795300
1822891
1849855
1874518
1901168
1926111
1953070
1982637
2017088
2059614
2106148
2171197
2245057
2293510
2352215
2454020
Crude Birth
2
Rate
16.3
17.0
16.6
16.7
16.4
16.3
16.2
16.0
16.3
16.1
16.0
15.2
15.2
15.0
14.8
14.6
14.4
14.0
14.0
13.8
13.3
13.0
12.8
12.5
12.8
13.3
13.8
14.2
14.0
13.8
13.5
13.6
13.8
Data Extracted from Midwives’ Notification System on 20 June 2014.
1
Source of population data: ABS Estimated Resident Populations for WA. Data previously reported here
has been updated from WA DoH Epidemiology Branch Downloads on 10 January 2014.
2
Crude birth rate is determined by the calculation: 1000 times Total infants born alive divided by mid-year
Total Population for the geographical area.
81
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Figure 18: Trends for number and crude birth rate for infants born alive in WA,
1980-2012
4.1.2.
Plurality
In 2012, there were 32,926 singleton infants born, representing 97.2 per cent of the total
infants born (33,862).
Infants born as twins totalled 930 and represented 2.7 per cent of all infants born. Two
sets of triplets were born (Table 81). The proportion of multiple infants born to Aboriginal
women was 3.3 per cent, more than the proportion for non-Aboriginal women (2.7 per
cent).
Table 81: Plurality of birth and maternal Aboriginal status for infants born in WA,
2012
Plurality
Single
Twin
Triplet
Total
Maternal Aboriginal status
Aboriginal
non-Aboriginal
No.
%
No.
%
1603
96.7
31323
97.3
54
3.3
876
2.7
6
0.0
1657 100.0
32205 100.0
Total
No.
%
32926
97.2
930
2.7
6
0.0
33862 100.0
Extracted from Midwives’ Notification System on 20 June 2014.
82
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.1.3.
Gender
During 2012, 51.4 per cent of all infants born were male with a male-female birth ratio of
1.06 which is 932 more male than female infants born (Table 82).
Table 82: Birth status and gender for infants born in WA, 2012
Condition at birth
Livebirth
Stillbirth
No.
%
No.
%
17273
51.4
120
50.6
16350
48.6
111
46.8
2
0.0
6
2.5
33625
100.0
237
100.0
Gender
Male
Female
Indeterminate
Total
Total
No.
17393
16461
8
33862
%
51.4
48.6
0.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
The trend data for 30 years displays a fluctuation in the percentage of males or females
born. For all years, more males than females were born reflecting national and
international birth ratios (Figure 19).
Figure 19: Trends for gender of infants born in WA, 1980-2012
55
54
52
51
50
49
48
47
46
Year of birth
Male
Female
83
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
45
1980
Percentage of all infants born
53
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.1.4.
Gestational age
Preterm birth (less than 37 weeks gestation) is associated with significant morbidity and
mortality in newborn infants.
In 2012, preterm birth occurred for 8.9 per cent of all infants born. In preterm infants,
93.0 per cent were born alive, 2.5 per cent were stillborn with death occurring during
labour, the remaining preterm infants (4.5 per cent) were stillborn where timing of death
was unknown or occurred before onset of labour.
For term infants, 99.9 per cent were born alive; less than five term infants were stillborn
with death occurring during labour (Table 83).
Table 83: Gestational age and birth status for infants born in WA, 2012
Gestation
(weeks)
Livebirth
20 to 27
28 to 32
33 to 36
< 37
37 to 44
Total
117
375
2324
2816
30809
33625
20 to 27
28 to 32
33 to 36
< 37
37 to 44
Total
42.9
93.5
98.8
93.0
99.9
99.3
20 to 27
28 to 32
33 to 36
< 37
37 to 44
Total
0.3
1.1
6.9
8.4
91.6
100.0
Birth Status
Stillbirth
Stillbirth
(before labour)
(during labour)
Number
82
74
25
***
28
***
135
***
24
***
159
78
Row Percentage
30.0
27.1
6.2
0.2
1.2
0.0
4.5
2.5
0.1
0.0
0.5
0.2
Column Percentage
51.6
94.9
15.7
1.3
17.6
1.3
84.9
97.4
15.1
2.6
100.0
100.0
Total
273
***
***
***
***
33862
100.0
100.0
100.0
100.0
100.0
100.0
0.8
1.2
6.9
8.9
91.1
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
Infants where timing of stillbirth was unspecified (19 infants) were included in “before labour counts”.
84
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.1.5.
Gestational age, birthweight and plurality
Plurality of birth influenced proportion of infants in gestational age and birthweight
groups.
Among singleton infants, 7.4 per cent were born before 37 weeks gestation (preterm)
and 5.3 per cent weighed less than 2,500 grams at birth. For term singleton infants, 1.6
per cent weighed less than 2,500 grams at birth (Table 84).
Table 84: Gestational age and birthweight for single birth infants born in WA,
2012
Birthweight
(grams)
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
≥ 4500
Total
Per cent of Total
20-27
No.
%
210
92.1
17
7.5
***
0.4
*** 100.0
*** 100.0
0.7
Gestation (weeks)
28-32
33-36
No.
%
No.
%
26
9.0
***
0.1
116
40.1
13
0.7
107
37.0
158
8.2
35
12.1
575
30.0
284
98.3
***
38.9
5
1.7
738
38.5
331
17.3
80
4.2
21
1.1
289 100.0
*** 100.0
0.9
5.8
37-44
No.
%
19
0.1
456
1.5
475
1.6
4292
14.1
12165
39.9
10154
33.3
2938
9.6
465
1.5
30489 100.0
92.6
Total
No.
%
237
0.7
146
0.4
285
0.9
1066
3.2
1734
5.3
5035
15.3
12496
38.0
10234
31.1
2959
9.0
465
1.4
32923 100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 3 infants where birthweight was unknown
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
Among infants from multiple births, the proportion born preterm was 63.0 per cent and
54.7 per cent weighed less than 2,500 grams at birth. For term multiple infants, 22.3 per
cent weighed less than 2,500 grams at birth (Table 85).
Table 85: Gestational age and birthweight for multiple birth infants born in WA,
2012
Birthweight
(grams)
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
Total
Per cent of Total
20-27
No.
%
40
90.9
***
9.1
*** 100.0
*** 100.0
4.7
Gestation (weeks)
28-32
33-36
No.
%
No.
%
5
4.5
***
***
45
40.5
***
***
47
42.3
74
16.2
14
12.6 204
47.2
111 100.0 280
64.4
- 133
30.3
22
5.1
111 100.0 435 100.0
11.9
46.5
37-44
No.
%
***
0.3
0.0
***
1.2
72
20.8
***
22.3
168
48.6
89
25.7
12
3.5
346 100.0
37.0
Total
No.
%
47
5.0
50
5.3
125
13.4
290
31.0
512
54.7
301
32.2
111
11.9
12
1.3
936 100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
85
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Among all infants born in 2012, the proportion born preterm was 8.9 per cent and 6.6
per cent weighed less than 2,500 grams at birth. For term infants, 1.8 per cent weighed
less than 2,500 grams at birth (Table 86).
Table 86: Gestational age and birthweight for infants born in WA, 2012
Gestation (weeks)
Birthweight
(grams)
< 1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
>= 4500
Total
Per cent of Total
20-27
No.
250
21
***
***
***
%
91.9
7.7
0.4
100.0
100.0
0.8
28-32
No.
31
161
154
49
395
5
400
%
7.7
40.1
38.4
12.2
98.5
1.2
100.0
1.2
33-36
No.
***
14
232
779
***
871
353
80
21
***
%
0.1
0.6
9.9
33.1
43.7
37.0
15.0
3.4
0.9
100.0
6.9
37-44
No.
***
23
528
***
4460
12254
10166
2938
465
***
%
0.0
0.1
1.7
1.8
14.5
39.7
33.0
9.5
1.5
100.0
91.1
Total
No.
284
196
410
1356
2246
5336
12607
10246
2959
465
33862
%
0.8
0.6
1.2
4.0
6.6
15.8
37.2
30.3
8.7
1.4
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 3 infants where birthweight was unknown.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
4.1.6.
Birthweight centiles
Birthweight centile charts have been compiled using information from publication on
Australian births by AIHW (Dobbins, et al. 2012). The following figures display
birthweight by gestational age in completed weeks for liveborn singleton infants of each
gender.
Figure 20: Birthweight centiles for singleton male infants born alive in WA, 2012
6000
5000
Birthweight (grams)
4000
99th
97th
95th
90th
75th
50th
3000
25th
10th
5th
3rd
1st
2000
1000
0
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
Gestational Age
86
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Figure 21: Birthweight centiles for singleton female infants born alive in WA, 2012
6000
5000
99th
97th
95th
90th
75th
50th
Birthweight (grams)
4000
25th
10th
5th
3rd
1st
3000
2000
1000
0
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
Gestational Age
4.1.7.
Birth status and place of birth of preterm infants
Among all preterm infants born alive at 23 to 31 weeks gestation, 89.7 per cent were
born in the tertiary maternity service. Of these infants, a small proportion, 2.8 per cent,
were born in private hospitals. The large proportion of preterm stillborn infants (74.4 per
cent) born at the tertiary maternity service is believed to reflect the state-wide practice of
in-utero transfer of compromised infants (Table 87).
Table 87: Birth status and place of birth of infants born at 23 to 31 weeks
gestation in WA, 2012
Place of birth
Tertiary
Public Metro
Public Country
Private
Total
23-25
%
89.8
3.4
5.1
1.7
100.0
Live Birth
Still Birth
Gestation (weeks)
Gestation (weeks)
26-28 29-31
Subtotal
23-25 26-28 29-31
Subtotal
Total
%
%
No.
%
%
%
%
No.
%
No.
%
90.0
89.6
323
89.7 85.4
69.6
50.0
58
74.4 381
87.0
2.0
2.0
8
2.2
13.0
14.3
5
6.4
13
3.0
7.0
4.5
19
5.3
9.8
17.4
14.3
10
12.8
29
6.6
1.0
4.0
10
2.8
4.9
21.4
5
6.4
15
3.4
100.0
100.0
360 100.0 100.0 100.0 100.0
78 100.0 438
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Includes infants that were “born before arrival” at birth site.
87
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Trend data for the period 1986 to 2012 indicate that the proportion of live births among
infants born at 23 to 31 weeks gestation has increased from a low of 74.3 per cent in
1987 to a high of 86.7 per cent in 2007. In 2012, the proportion of live births among
these infants was 82.2 per cent (Table 88).
Table 88: Trends for birth status and place of birth of infants born at 23 to 31
weeks gestation in WA, 1986-2012
Year
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Tertiary
Live Birth
Fetal Death
No.
%
No.
%
212
67.1
46
14.6
182
65.0
48
17.1
250
73.1
48
14.0
271
78.1
36
10.4
206
72.3
41
14.4
220
72.1
34
11.1
231
77.5
32
10.7
200
69.9
40
14.0
244
74.4
32
9.8
225
75.0
37
12.3
226
71.7
45
14.3
265
78.4
35
10.4
264
78.1
37
10.9
246
79.4
34
11.0
268
76.6
44
12.6
261
77.2
35
10.4
219
73.7
40
13.5
230
76.4
30
10.0
283
78.8
36
10.0
286
77.9
36
9.8
302
77.8
43
11.1
317
79.4
38
9.5
328
77.5
44
10.4
313
72.3
46
10.6
297
75.4
49
12.4
305
76.3
45
11.3
323
73.7
58
13.2
Other
Total
Live Birth
Fetal Death
Live Birth
Fetal Death
No.
%
No.
%
No.
%
No.
%
33
10.4
25
7.9
245
77.5
71
22.5
26
9.3
24
8.6
208
74.3
72
25.7
24
7.0
20
5.8
274
80.1
68
19.9
20
5.8
20
5.8
291
83.9
56
16.1
19
6.7
19
6.7
225
78.9
60
21.1
23
7.5
28
9.2
243
79.7
62
20.3
21
7.0
14
4.7
252
84.6
46
15.4
22
7.7
24
8.4
222
77.6
64
22.4
22
6.7
30
9.1
266
81.1
62
18.9
20
6.7
18
6.0
245
81.7
55
18.3
22
7.0
22
7.0
248
78.7
67
21.3
22
6.5
16
4.7
287
84.9
51
15.1
16
4.7
21
6.2
280
82.8
58
17.2
18
5.8
12
3.9
264
85.2
46
14.8
27
7.7
11
3.1
295
84.3
55
15.7
24
7.1
18
5.3
285
84.3
53
15.7
25
8.4
13
4.4
244
82.2
53
17.8
23
7.6
18
6.0
253
84.1
48
15.9
23
6.4
17
4.7
306
85.2
53
14.8
27
7.9
16
4.4
315
85.8
52
14.2
29
7.5
14
3.6
331
85.3
57
14.7
29
7.3
15
3.8
346
86.7
53
13.3
31
7.3
20
4.7
359
84.9
64
15.1
51
11.8
23
5.3
364
84.1
69
15.9
29
7.4
19
4.8
326
82.7
68
17.3
26
6.5
24
6.0
331
82.8
69
17.3
37
8.4
20
4.6
360
82.2
78
17.8
Extracted from Midwives’ Notification System on 20 June 2014.
Denominator for all percentages in above table was total infants born in the year at a gestation 23 to 31 completed weeks.
88
Western Australia’s Mothers and Babies 2012, 30th Annual Report
A tertiary maternity service is considered the optimal birth place for infants born alive at
these gestations. The proportion of infants born at the tertiary maternity service ranged
between 86.5 per cent in 1986 and 94.3 per cent 1998. In 2012, the proportion of
preterm liveborn infants born at the tertiary maternity service was 92.7 per cent (Table
88 and Figure 22).
Figure 22: Trends for place of birth of infants born alive at 23 to 31 weeks
gestation in WA, 1986-2012
100%
90%
70%
60%
50%
40%
30%
20%
10%
0%
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Proportion of Livebirths
80%
Year of Birth
Preterm livebirths in Teaching Hospital
Preterm Livebirths Other Birth Sites
89
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.1.8.
Birthweight
In 2012, an average birthweight of 3335.7 grams, with a standard deviation of 601.1
grams was recorded for all infants born. The median birthweight was 3380 grams.
The highest proportion of all infants born, 37.2 per cent, weighed between 3000 and
3499 grams. A further 30.3 per cent of infants weighed between 3500 and 3999 grams.
Infants less than 2500 grams represented 6.6 per cent of all infants born.
For all infants born alive in 2012, there was an average birthweight of 3351.9 grams,
with a standard deviation of 565.1 grams. The median birthweight was 3380 grams.
Infants less than 2,500 grams represented 6.1 per cent of all liveborn infants.
Of all the infants stillborn in 2012, 86.9 per cent had a birthweight less than 2,500 grams
(Table 89).
Of the 2,246 infants with a birthweight less than 2,500 grams, 2,040 (90.8 per cent were
born alive.
Table 89: Birthweight and birth status for infants born in WA, 2012
Birthweight
(grams)
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
≥ 4500
Total
Condition at Birth
Live Birth
Fetal Death
No.
%
No.
%
122
0.4
162
68.4
185
0.6
11
4.6
390
1.2
20
8.4
1343
4.0
13
5.5
2040
6.1
206
86.9
5324
15.8
12
5.1
12597
37.5
10
4.2
10241
30.5
5
2.1
2957
8.8
***
0.8
465
1.4
33624
100.0
235
100.0
Total
No.
284
196
410
1356
2246
5336
12607
10246
2959
465
33859
%
0.8
0.6
1.2
4.0
6.6
15.8
37.2
30.3
8.7
1.4
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 3 infants where birthweight was unknown
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
90
Western Australia’s Mothers and Babies 2012, 30th Annual Report
In 2012, 19.2 per cent of infants with a birthweight of at least 2,500 grams received
resuscitation at birth. In comparison, 50.0 per cent of infants with a birthweight less than
2,500 grams received resuscitation ((Table 90).
Of infants that were resuscitated at birth most had suction, oxygen or ventilation by Bag
and Mask. The high proportion of infants receiving “Other” resuscitation included those
that received Continuous Positive Airway Pressure or CPAP (Table 90).
Table 90: Birthweight and resuscitation for infants born alive in WA, 2012
Resuscitation methods
1-None
2-Suction Only
3-Oxygen Therapy
4-Bag & Mask
5-Intubation
6-External cardiac massage
8-Other
Any resuscitation
% receiving any resus
Total
1
< 1500
23
***
10
37
80
5
150
284
92.5
307
Birthweight (grams)
1500-1999 2000-2499
147
851
15
46
25
96
70
164
16
11
6
117
169
243
492
62.3
36.6
390
1343
≥ 2500
25511
1474
1698
1583
87
54
1177
6073
19.2
31584
Total
No.
%
26532
78.9
1537
4.6
1829
5.4
1854
5.5
194
0.6
65
0.2
1613
4.8
7092
21.1
33624 100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
1
Description of resuscitation received at birth was limited to reporting only the most “intensive” method as determined by the order
of these values displayed here.
91
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.1.9.
Birth status and place of birth
There were 33,625 (99.3 per cent) infants liveborn and 237 (0.7 per cent) stillborn in
2012. These infants include those born from termination of pregnancy when gestation
was 20 weeks or greater. Of the stillborn infants, many died before onset of labour or
had time of death not specified (67.1 per cent).
The stillbirth rate in 2012 was 7.0 per 1000 births with an intrapartum fetal death rate of
2.3 per 1000 births. Of the infants that died during labour, 91.0 per cent were born at the
tertiary maternity service. The highest stillbirth rate was in births occurring at the tertiary
maternity service (25.5 per 1000 births) reflecting the referral of mothers with extreme
prematurity or other high-risk condition in pregnancy (Table 91).
Table 91: Birth status and place of birth for infants born in WA, 2012
Livebirths
No.
%
Birth Status
Fetal Death Before
2
Labour
No.
%
Fetal Death
During Labour
No.
%
Total
5956
8747
12968
77
17.7
26.0
38.6
0.2
53.5
13.2
15.1
2.5
91.0
3.8
1.3
6112
8771
12992
82
18.0
25.9
38.4
0.2
25.5
2.7
1.8
61.0
Country
Regional public
Other public
Private
BBA
3312
1475
846
27
9.8
4.4
2.5
0.1
9.4
1.3
3.8
1.3
2.6
1.3
3329
848
1481
30
9.8
2.5
4.4
0.1
5.1
2.4
4.1
100.0
201
16
33625
0.6
0.0
100.0
99.3
100.0
0.5
100.0
0.2
201
16
33862
0.6
0.0
100.0
100.0
0.0
0.0
8.4
Non-hospital
Home births
BBA
Total
Proportion
159
81
No.
Stillbirth
1
rate
Place of birth
Metropolitan
Tertiary
Public
Private
BBA
%
Extracted from Midwives’ Notification System on 20 June 2014.
BBA (Born Before Arrival) are those infants born enroute to hospital or at home when not attended by a health professional.
1
Number of infants stillborn per 1000 infants born.
2
There were 19 infants reported as stillborn with no indicator of when fetal death occurred, these infants
are counted with those where death occurred before onset of labour.
92
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.1.10. Plurality of infants born
In 2012, there were 32,926 singleton infants born, representing 97.2 per cent of total
infants born. Twin infants comprised 2.7 per cent and triplets 0.1 per cent of all infants
born (Table 92).
The occurrence of twins born in 2012 in WA was 1 per 70.8 singleton. A natural rate of
1 per 89 would be expected when applying Hellin’s law1. The higher occurrence of twins
born in 2012 than expected could be attributed to the increased use of fertility
treatments such as assisted reproductive technology (Tough, et al. 2002).
Of the 936 infants of multiple births, 2.4 per cent were stillborn compared with 0.7 per
cent of singleton infants who were stillborn (Table 92).
Table 92: Birth status and plurality of birth for infants born in WA, 2012
Plurality
Single
Twin
Triplet
Total
Single
Twin
Triplet
Total
Single
Twin
Triplet
Total
Birth Status
Livebirth
Stillbirth
Number
32711
215
908
22
6
33625
237
Column Per cent
97.3
90.7
2.7
9.3
0.0
100.0
100.0
Row Per cent
99.3
0.7
97.6
2.4
100.0
99.3
0.7
Total
32926
930
6
33862
97.2
2.7
0.1
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
1
2
Hellin's Law is the principle that one in about 89 pregnancies ends in the birth of twins, triplets once in 89 births,
3
and quadruplets once in 89 births.
93
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.1.11. Plurality, presentation and birth method
In 2012, there were 1,260 singleton infants with a breech presentation at birth, of these
9.9 per cent were born vaginally. For infants from multiple pregnancies, 275 had a
breech presentation and 20.4 per cent were born vaginally.
Of the 31,188 singleton infants that had vertex presentation, 68.2 per cent were born
vaginally, 52.3 per cent were spontaneous, 12.9 per cent were delivered with vacuum
extraction and 3.0 per cent by forceps (Table 93).
Table 93: Fetal presentation, method of birth and plurality of birth for infants born
in WA, 2012
Birth method
Fetal presentation
Breech
Plurality of Birth
Multiple
Single
Multiple
Number
178
122
53
39
19
***
***
202
712
116
201
423
103
639
1260
275
Column Percentage
27.9
9.7
19.3
6.1
3.0
0.2
1.1
31.6
56.5
42.2
31.5
33.6
37.5
100.0
100.0
100.0
Vertex
Single
Spontaneous
Breech
Vacuum
Forceps
Elective CS
Emergency CS
Total
16319
4017
931
5032
4889
31188
Spontaneous
Breech
Vacuum
Forceps
Elective CS
Emergency CS
Total
52.3
12.9
3.0
16.1
15.7
100.0
Other
Single
Total
Multiple
252
42
16
61
107
478
11
11
22
16749
175
4098
972
6134
5734
33862
52.7
8.8
3.3
12.8
22.4
100.0
50.0
50.0
100.0
49.5
0.5
12.1
2.9
18.1
16.9
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Other presentations include face, brow, compound, transverse, other or unspecified.
Each infant born from a multiple pregnancy may have a different method of birth.
Unsuccessful vacuum extraction, unsuccessful forceps and forceps lift out at CS are not specified in this table.
The percentages for CS presented here do not represent a “caesarean section rate” they are the percentage of infants born by CS;
multiple babies may be born from one CS.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
94
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.2. Infant extra-uterine adjustment
4.2.1.
Apgar score at one minute and five minutes
Apgar scoring is a practical method of evaluating the physical condition of a newborn
infant shortly after birth and their response to resuscitation should it be required. The
Apgar score is calculated based on the infant’s heart rate, respiratory effort, muscle
tone, skin colour, and reflexes. Stillborn infants have a total score of 0 recorded.
In 2012, for liveborn infants with an Apgar score at one minute reported, 85.3 per cent
had an Apgar Score of 8 to 10. While 1.7 per cent infants had an Apgar score of less
than four at one minute of age.
Among all infants born alive with Apgar score reported, 91.1 per cent established
spontaneous respiration within the first minute of life.
Seventeen liveborn infants had no Apgar score at one minute reported. Sixteen of these
infants were born before arrival at health service (Table 94).
Table 94: Apgar score at one minute and time to spontaneous respiration for
infants born alive in WA, 2012
Time to
Spontaneous
Respiration
(mins)
≤1
2-3
4-6
≥7
1
Unknown
Total
Row Percentage
0-3
No.
45
184
153
84
92
558
Apgar Score at 1 Minute
4-7
%
8.1
33.0
27.4
15.1
16.5
100.0
1.7
No.
2420
1335
405
94
117
4371
%
55.4
30.5
9.3
2.2
2.7
100.0
13.0
8-10
No.
28163
441
47
10
18
28679
Total
%
98.2
1.5
0.2
0.0
0.1
100.0
85.3
No.
30628
1960
605
188
227
33608
%
91.1
5.8
1.8
0.6
0.7
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
17 infants with no Apgar score at 1 minute reported were excluded from the table above.
1
The time taken for newborn infants to establish spontaneous respiration following intubation or when not
attended by a health professional is not reported to the collection.
95
Western Australia’s Mothers and Babies 2012, 30th Annual Report
In 2012, for liveborn infants with an Apgar score at five minutes reported, 96.7 per cent
had an Apgar Score of 8 to 10. While 0.2 per cent of liveborn infants had an Apgar
score of less than four at five minutes of age.
Fifteen liveborn infants had an unknown Apgar score at five minutes. Fourteen of these
infants were born before arrival at health service (Table 95).
Table 95: Apgar score at five minutes and time to spontaneous respiration for
infants born alive in WA, 2012
Time to
Spontaneous
Respiration
≤1
2-3
4-6
≥7
1
Unknown
Total
Row Percentage
0-3
No.
11
***
***
15
26
60
Apgar Score at 5 Minutes
4-7
8-10
%
No.
%
No.
%
18.3
260
24.5
30359
93.4
6.7
256
21.7
1700
5.2
6.7
256
26.4
345
1.1
25.0
141
13.7
32
0.1
43.3
123
13.6
78
0.2
100.0
1036
100.0
32514
100.0
0.2
3.1
96.7
Total
No.
30630
1960
605
188
227
33610
%
91.1
5.8
1.8
0.6
0.7
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
15 infants with an unknown Apgar score at 5 minutes were excluded from the table above.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
96
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.2.2.
Infant resuscitation
Only one method of infant resuscitation is reported by midwives for each infant.
Reporting is hierarchical with the most intensive method reported. A hierarchy from 1
being the least intensive to 8 being the most intensive is indicated in the data table. In
2012, midwives may have reported medications like Adrenaline or Narcan or continuous
positive airway pressure (CPAP) as “Other”.
Of the 33,625 infants born alive in 2012, 21.1 per cent received some form of
resuscitation. A method of “Other” was reported for 4.8 per cent of these liveborn
infants. The proportion that received external cardiac massage was 0.2 per cent and 0.6
per cent had endotracheal intubation without external cardiac massage. Assisted
ventilation with bag and mask was provided to 5.5 per cent, 5.4 per cent received
oxygen with or without suction and only suction was required by 4.6 per cent of infants
(Table 96).
Table 96: Resuscitation received by infants born alive in WA, 2012
Liveborn Infants
No.
%
26532
78.9
1537
4.6
1829
5.4
1854
5.5
194
0.6
66
0.2
1613
4.8
33625
100.0
Resuscitation method
1-None
2-Suction Only
3-Oxygen Therapy
4-Bag & Mask
5-Intubation
6-External Cardiac Massage
1
8-Other
Total
Extracted from Midwives’ Notification System on 20 June 2014.
Apgar score at 5 minutes often reflects the response by an infant to resuscitation if it
was required. Of infants born alive in 2012 with an Apgar score at five minutes of 8 to
10, 81.5 per cent required no resuscitation, 5.3 per cent received oxygen therapy, 4.6
per cent received suction only and 4.7 per cent required assisted ventilation using a bag
and mask (Table 97).
Table 97: Resuscitation and Apgar score at five minutes for infants born alive in
WA, 2012
0-3
Resuscitation methods
1-None
2-Suction Only
3-Oxygen Therapy
4-Bag & Mask
5-Intubation
6-External Cardiac Massage
1
8-Other
Total
No.
5
6
14
9
26
60
Apgar Score at 5 Minutes
4-7
8-10
%
No.
%
No.
%
8.3
29
2.8
26484 81.5
27
2.6
1510
4.6
- 102
9.8
1727
5.3
10.0 328
31.7
1520
4.7
23.3
98
9.5
82
0.3
15.0
32
3.1
25
0.1
43.3 420
40.5
1166
3.6
100.0 1036
100.0
32514 100.0
Total
No.
%
26518 78.9
1537
4.6
1829
5.4
1854
5.5
194
0.6
66
0.2
1612
4.8
33610 100.0
Extracted from Midwives’ Notification System on 20 June 2014.
15 infants with no Apgar score at 5 minutes reported were excluded from the table above.
1
Other Resuscitation Methods included medications. The “Other” option is considered the highest value
for resuscitation methods. Infants that have had the “Other” option reported may or may not have had any
other methods employed.
97
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.3. Birth trauma
Infant birth trauma can occur because of duration of time the presenting part of the fetus
is well applied to the maternal cervix during labour. Trauma can also be a result of
application of a vacuum cup or forceps to facilitate birth. Manipulation of a fetus for
delivery can be required for situations like shoulder dystocia, breech delivery or
compound presentation.
In 2012, the most frequently reported birth trauma was chignon that affected 2.4 per
cent of all infants or 3.6 per cent of infants born vaginally. The most frequently occurring
trauma in infants born by caesarean section was bruising of the scalp (1.7 per cent).
Trauma like Erb’s Palsy or fracture of clavicle associated with a difficult extraction was
reported for 25 infants, affecting 0.1 per cent of all infants born and all infants born
vaginally (Table 98).
Table 98: Birth trauma to infants born in WA, 2012
Type of Birth Trauma
Cephalhaematoma
Chignon
Bruising of scalp
Other trauma to scalp
Birth trauma to face/facial nerve/eye
Birth trauma to skeleton, unspecified
Erb's Palsy/Fracture of clavicle
Other specified birth trauma
Total infants by birth method
Birth Method
Caesarean
Vaginal
No.
%
No.
%
19
0.2
162
0.7
24
0.2
794
3.6
197
1.7
241
1.1
90
0.8
334
1.5
6
0.1
13
0.1
***
0.0
***
0.0
25
0.1
***
0.2
***
0.1
11868
21994
Total
No.
%
181
0.5
818
2.4
438
1.3
424
1.3
19
0.1
10
0.0
25
0.1
46
0.1
33862
Extracted from Midwives’ Notification System on 20 June 2014.
Percentages are calculated as proportions of all infants with the same birth method.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
4.4. Birth defects
A birth defect was suspected in 1,027 infants born in 2012, a rate per 1000 of 30.3.
Suspected conditions included genetic anomalies like trisomies, structural anomalies
like extra digits or cardiac anomalies, birth marks and missing umbilical cord blood
vessels.
Midwives who reported a birth defect enabled early advice of potential cases to the WA
Register for Developmental Anomalies (WARDA). WARDA staff were able to ensure
reporting of birth defects by medical practitioners to WARDA. Ascertainment of birth
defects for a birth cohort is not considered complete until reported by a medical
practitioner and the child is 6 years of age. More detailed information including trends
over birth years is available for births occurring 1980 to 2013 in the WARDA Annual
Report at
http://kemh.health.wa.gov.au/services/register_developmental_anomalies/documents/2
015_Annual_Report_of_the_WA_Register_of_Developmental_Abnormalities.pdf
http://www.kemh.health.wa.gov.au/services/register_developmental_anomalies/docume
nts/2012_Annual_Report_of_the_WA_Register_of_Developmental_Abnormalities.pdfor
by request to the Western Australian Register of Developmental Anomalies.
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Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.5. Infant outcome
4.5.1.
Admission to Special Care Nursery
In 2012, there was one birth site in Western Australia with a Level 3 and Level 2 Special
Care Nursery (SCN); eleven other birth sites had a Level 2 SCN. Sites with no SCN
could have provided neonatal care for unstable infants for a short time, usually less than
1 day. Infant stays in SCN of less than one day are not reported in Table 99.
Of 33,625 liveborn infants, 11.4 per cent were admitted to a SCN (Level 2 or 3) at their
birth site with a SCN length of stay of at least one day reported.
Infants of a multiple birth had a 52.2 per cent proportion admitted to SCN and singleton
infants had a 10.3 per cent proportion admitted to SCN.
The SCN length of stay exceeded 7 days for 22.9 per cent of singleton infants and 56.0
per cent of infants from multiple births.
Table 99: Length of stay in Special Care Nursery and plurality of birth for infants
born alive in WA, 2012
Plurality
Single
1
Length of Stay (days)
1
2
3
4
5
6
7
8-14
15-20
21-28
29-60
61-90
91-180
More than 7
Total admitted ≥ 1 day
Total liveborn
Proportion of liveborn
admitted ≥ 1 day
No.
964
585
394
221
193
130
102
348
139
67
127
56
34
771
3360
32711
Total
%
28.7
17.4
11.7
6.6
5.7
3.9
3.0
10.4
4.1
2.0
3.8
1.7
1.0
22.9
100.0
Multiple
No.
%
40
8.4
37
7.8
35
7.3
25
5.2
34
7.1
26
5.5
13
2.7
86
18.0
63
13.2
30
6.3
52
10.9
18
3.8
18
3.8
267
56.0
477
100.0
914
10.3
52.2
No.
1004
622
429
246
227
156
115
434
202
97
179
74
52
1038
3837
33625
%
26.2
16.2
11.2
6.4
5.9
4.1
3.0
11.3
5.3
2.5
4.7
1.9
1.4
27.1
100.0
11.4
Extracted from Midwives’ Notification System on 20 June 2014.
1
Excludes infants transferred from a birth site to another site for admission to SCN and excludes infants
with a stay in SCN at the birth site of less than 24 hours.
99
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.5.2.
Transfer from birth place
Transfer of infants to another hospital following birth occurred for 4.7 per cent of
liveborn infants. Transfer may have been undertaken when a higher level of care was
required than was available at the birth site or when lower level of care provision was
appropriate for ongoing care before discharge (Table 100).
In the neonatal period (before 28 days of age) 0.1 per cent of infants died before
discharge from their birth site (Table 100). (see Table 104).
Information about infants that were stillborn or died within one year of birth was
collected for review by the WA Perinatal and Infant Mortality Committee in a separate
process.
Table 100: Transfer from birth place to other hospital for infants born alive in WA,
2012
Place of Birth
Metropolitan
Tertiary
Other Public
Private
Country
Regional
Other Public
Private
Homebirth
Total
Discharge Outcome
Transferred
Died
Discharged Home
No.
%
No.
%
No.
%
Total
No.
%
934
212
145
15.6
2.4
1.1
23
***
***
0.7
***
***
5025
8562
12841
84.0
5982
97.5
8778
98.9 12988
100.0
100.0
100.0
225
50
21
7
1594
6.8
3.4
2.5
3.2
4.7
***
***
44
***
***
0.1
3103
1432
825
210
31998
93.2
3331
96.6
1483
97.5
846
96.8
217
95.2 33625
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
100
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Of the 31,990 liveborn infants with an outcome of discharge from their birth site 78.9 per
cent4 had a length of stay at their birth site between two and seven days. Of infants that
stayed longer than a week before they were discharged home, 2.1per cent stayed up to
two weeks, the remaining 1.2 per cent stayed more than two weeks (Table 101).
In 2012, 18.3 per cent of infants with “normal” birthweight (2,500 grams or more) stayed
at their birth site for one day or less.
Infants with low birthweight spent more days at the birth site. Of the 438 infants that
stayed at the birth site for more than two weeks, 87.4 per cent had low birthweight
(Table 101).
Table 101: Length of stay at birth site before discharge home by birthweight for
infants born alive in WA, 2012
Birthweight
(grams)
≤1
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
≥ 4500
>= 2500
Total
30
30
729
2261
1940
594
90
5614
5644
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
≥ 4500
>= 2500
Total
2.8
2.2
14.5
18.4
19.4
20.6
20.2
18.3
17.6
<1000
1000-1499
1500-1999
2000-2499
< 2500
2500-2999
3000-3499
3500-3999
4000-4499
≥ 4500
>= 2500
Total
0.5
0.5
12.9
40.1
34.4
10.5
1.6
99.5
100.0
Length of Stay (days)
2-7
8-14
> 14
Number
68
74
26
31
103
683
202
138
709
233
383
4022
241
39
9899
108
6
7983
69
7
2267
22
***
351
***
24522
444
55
25231
677
438
Row Percentage
100.0
100.0
16.3
19.4
64.2
64.9
19.2
13.0
52.3
17.2
25.6
79.9
4.8
0.7
80.7
0.9
0.1
79.8
0.7
0.1
78.6
0.8
0.1
78.9
0.9
80.0
1.4
0.2
78.9
2.1
1.2
Column Percentage
15.5
16.9
0.1
4.6
23.5
2.7
29.8
31.5
2.8
34.4
87.4
15.9
35.6
8.9
39.2
16.0
1.4
31.6
10.2
1.6
9.0
3.2
0.7
1.4
0.6
97.2
65.6
12.6
100.0
100.0
100.0
Total
68
74
160
1053
1355
5031
12274
9999
***
***
30635
31990
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
0.2
0.2
0.5
3.3
4.2
15.7
38.4
31.3
9.0
1.4
95.8
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Includes homebirths in midwife's care where discharge date equals birth date.
Excludes infants that were stillborn or died or were transferred to another site.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
101
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Gestational age is a better predictor of infant endurance than birthweight. Length of
Stay at birth site of one day or less for preterm infants could be explained by transfer to
another health service or early neonatal death.
The proportion of liveborn infants of gestational age 33 to 36 weeks that stayed for two
weeks or more at birth site and discharged home alive was 86.6 per cent (Table 102).
Table 102: Length of stay at birth site before discharge home by gestation for
infants born alive in WA, 2012
Gestation age
33-36 weeks
37-44 weeks
Total
33-36 weeks
37-44 weeks
Total
33-36 weeks
37-44 weeks
Total
Length of Stay (days)
≤1
2-7
8-14
Number
57
1161
368
5587
24069
308
5644
25230
676
Row Percentage
3.2
64.8
20.5
18.6
80.2
1.0
17.8
79.4
2.1
Column Percentage
1.0
4.6
54.4
99.0
95.4
45.6
100.0
100.0
100.0
>14
Total
207
32
239
1793
29996
31789
11.5
0.1
0.8
100.0
100.0
100.0
86.6
13.4
100.0
5.6
94.4
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Excludes 201 infants of gestational age less than 33 weeks. These infants contributed low values to most cells of the table and were
excluded to suppress values less than 5.
Other infants born alive were transferred from the birth site or died before discharge. Of
these 821 were preterm and 806 were 37 weeks gestation or more (Table 103).
Table 103: Length of stay at birth site by gestation for infants who were
transferred from birth or died in WA, 2012
Gestation age
20-27 weeks
28-32 weeks
33-36 weeks
Less than 37 weeks
37-44 weeks
TOTAL
≤1
17
39
115
171
500
671
Length of Stay (days)
2-7
8-14
Number
6
2
17
38
257
113
280
153
294
8
574
161
>14
Total
28
144
45
217
4
221
53
238
530
821
806
1627
Extracted from Midwives’ Notification System on 20 June 2014.
102
Western Australia’s Mothers and Babies 2012, 30th Annual Report
4.5.3.
Liveborn infant length of stay at birthplace
Infant length of stay at birth place reported by midwives can be affected by infant
birthweight, infant gestation, infant condition and maternal length of stay. At all maternity
services a well infant will not usually be discharged from the birth site before an unwell
mother.
Trend data in Figure 23 illustrate a change in the proportion of infants discharged home
within a day of birth. From a low of 0.6 per cent in 1981 a proportion of 10.1 per cent
was attained by 1999. By 2012, the proportion of infants discharged home on day of
birth or the day after birth was 17.6 per cent. The Australian proportion for 2012 was
17.0 per cent (Hilder, et al. 2014)
Figure 23: Trends for infants discharged Home within one day of birth in WA,
1980-2012
20
Proportion of Infants Discharged
18
16
14
12
10
8
6
4
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
0
1980
2
LOS 1 day or less
Proportion of all infants discharged alive from site of birth without transfer to another hospital.
103
Western Australia’s Mothers and Babies 2012, 30th Annual Report
5. Perinatal Mortality
Perinatal deaths include stillborn infants (fetal deaths) where the infant died before the
onset of labour or during labour, and neonatal deaths where the infant died in the
neonatal period, between birth and the 28th day of life.
The WA Midwives Notification System includes data for infants of 20 weeks gestation
that were born as a result of termination of a pregnancy. As these infants cannot be
distinguished from other infants they contribute to the perinatal mortality rate presented
here. A report for calendar year, 2012 from the WA Abortion Notification System
(Hutchinson, Joyce and Cheong 2013) indicates that these cases number 52 and would
comprise 18.3 per cent of the perinatal deaths described in text and tables below.
There were 237 perinatal deaths occurring for infants born in 2012 from pregnancies of
20 weeks or more gestation. There were 237 stillborn infants and 48 born alive who
died in the neonatal period. There was a perinatal mortality rate of 8.4 per 1000 infants
born, a fetal mortality rate of 7.0 per 1000 infants born and a neonatal mortality rate of
1.4 per 1000 infants born alive (Table 104).
Mortality rates for infants of Aboriginal mothers were between two and three times
higher than for infants of non-Aboriginal mothers in all categories.
For more information about perinatal mortality in Western Australia go to the reports of
the WA Perinatal Mortality Committee at:
http://www.health.wa.gov.au/publications/subject_index/p/Perinatal_infant_maternal.cfm
.
Table 104: Perinatal mortality and maternal Aboriginal status for infants born in
WA, 2012
Maternal Aboriginal Status
Aboriginal
non-Aboriginal
1
2
Number
Rate
Number
Rate
Fetal deaths
28
16.9
209
6.5
Neonatal death
7
4.3
41
1.3
Perinatal deaths
35
21.1
250
7.8
Mortality Type
Total
Number
237
48
285
3
Rate
7.0
1.4
8.4
Extracted from the Perinatal Mortality Database 7 January 2015.
1
The Denominators used for infants of Aboriginal mothers were 1,657 total infants born and 1,629 infants
born alive.
2
The Denominators used for infants of non-Aboriginal mothers were 32,205 total infants born and 31,996
infants born alive.
3
The Denominators used were for Total infants born in WA 33,862 and 33,625 infants born alive.
104
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Since 1994, infants of Aboriginal mothers had a perinatal mortality rate ranging from a
high of 25.8 per 1000 infants born in 1999 to a low of 14.8 in 2007. The perinatal
mortality rate for 2012 was 21.1 per 1000 infants born (Table 105).
Table 105: Trends for perinatal mortality by maternal Aboriginal status for infants
born in WA, 1994-2012
Year of birth
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Maternal Aboriginal Status
Aboriginal rate Non-Aboriginal rate
22.7
10.2
21.9
10.0
21.4
11.1
25.9
8.6
17.8
8.6
25.8
9.0
24.2
9.9
17.6
9.2
25.1
8.0
23.9
8.6
16.5
9.3
19.8
9.5
24.3
8.5
14.8
7.8
19.6
8.6
20.4
9.4
21.2
8.5
23.6
9.6
21.1
7.8
Total rate
10.9
10.7
11.7
9.7
9.1
10.1
10.8
9.7
9.2
9.6
9.8
10.2
9.5
8.2
9.3
10.0
9.2
10.3
8.4
Extracted from the Perinatal Mortality Database 17 January 2014.
5.1.1.
Perinatal mortality by gestational age in WA
Early gestational age corresponded with a higher perinatal death rate. When infants
born at gestations of 20 or 21 completed weeks were excluded, the perinatal mortality
rate was 6.2 per 1000 infants born (Table 106).
Table 106: Perinatal mortality by gestation for infants born in WA, 2012
Gestation
≥ 20 weeks
≥ 22 weeks
Fetal death rate
7.0
4.9
Neonatal death rate
1.4
1.4
Perinatal death rate
8.4
6.2
Extracted from the Perinatal Mortality Database 7 January 2015.
Includes infants of at least 20 weeks gestation that may have had severe congenital abnormalities.
5.1.2.
Perinatal mortality by birthweight in WA
Low birthweight corresponded with a higher perinatal death rate. When infants with
birthweight less than 400 grams were excluded, the perinatal mortality rate was 6.2 per
1000 infants. When infants with birthweight less than 500 grams were excluded, the
perinatal mortality rate was 5.0 per 1000 infants born (Table 107).
Table 107: Perinatal mortality by birthweight for infants born in WA, 2012
Birthweight (grams)
≥ 400 grams
≥ 500 grams
Fetal death rate
4.9
3.8
Neonatal death rate
1.3
1.2
Perinatal death rate
6.2
5.0
Extracted from the Perinatal Mortality Database 7 January 2015.
Excludes 72 cases where birthweight was less than 400 grams.
Excludes 3 cases where birthweight was not reported.
Includes infants of at least 20 weeks gestation that may have had severe congenital abnormalities.
105
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Of stillborn infants, 87.7 percent had a birthweight less than 2,500 grams. Of infants
who died in the neonatal period a lower proportion were in this low birthweight category
(61.7 per cent). The proportion of perinatal deaths that were low birthweight infants was
83.3 per cent (Table 108).
Table 108: Birthweight for infants that died in perinatal period and were born in
WA, 2012
Mortality type
Fetal deaths
Birthweight (grams)
Total Number
Neonatal deaths
Number
235
Column Percentage
68.9
4.7
8.5
5.5
87.7
5.1
4.3
3.0
100.0
< 1000
1000–1499
1500–1999
2000–2499
< 2500
2500–2999
3000–3499
≥ 3500
Total Percentage
Perinatal deaths
47
282
36.2
12.8
6.4
6.4
61.7
8.5
21.3
8.5
100.0
63.5
6.0
8.2
5.7
83.3
5.7
7.1
3.9
100.0
Extracted from the Perinatal Mortality Database and Midwives Notification System 7 January 2015.
Excludes 3 cases where birthweight was not reported.
For infants of multiple births, the perinatal mortality rate was 27.8 per 1000 infants.
Almost four times the rate for singleton infants of 7.9 per 1000 (Table 109).
Table 109: Perinatal mortality and plurality of birth for infants born in WA, 2012
Plurality
Single
Multiple
Total
Fetal death
No.
Rate
215
6.5
22
23.5
237
7.0
Mortality type
Neonatal death
No.
Rate
44
1.3
4
4.4
48
1.4
Perinatal death
No.
Rate
259
7.9
26
27.8
285
8.4
Extracted from the Perinatal Mortality Database 7 January 2015.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
A neonatal death (the death of a liveborn baby during the first 28 days of life) is more
likely to occur in the first day of life. In 2012, 35.4 per cent of neonatal deaths occurred
in infants aged less than one day (Table 110).
Table 110: Age at neonatal death for infants born in WA, 2012
Age at neonatal death
< Day 1
Day 1
Day 2
Day 3-7
Day 8-21
Day 22-28
Total
Neonatal Deaths
No.
%
17
35.4
1
2.1
3
6.3
15
31.3
10
20.8
2
4.2
48
100.0
Extracted from the Perinatal Mortality Database 7 January 2015.
Values <5 are suppressed and indicated with ***, values in the same row/column are provided as a range to prevent calculation of
the suppressed value.
106
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Autopsy occurred for 66.7 per cent of infants that were stillborn (fetal death) and 35.4
per cent of infants that died in the neonatal period (Table 111).
Table 111: Autopsy requests for infants that died in perinatal period in WA, 2012
Autopsy
Yes
No/Unknown
Total
Fetal deaths
No.
%
158
66.7
79
33.3
237
100.0
Mortality Type
Neonatal deaths
No.
%
17
35.4
31
64.6
48
100.0
Perinatal deaths
No.
%
175
61.4
110
38.6
285
100.0
Extracted from the Perinatal Mortality Database 7 January 2015.
The principal known causes for fetal death were lethal birth defect (30.0 per cent) and
extremely low birthweight of less than 1000 grams (43.0 per cent). Among infants that
died neonatally, extremely low birthweight was the cause of death determined for 41.7
per cent and lethal birth defect for 29.2 per cent (Table 112).
Table 112: Causes of perinatal death for infants born in WA, 2012
Cause of Perinatal death
Lethal birth defect
Extremely low birthweight (< 1000 grams)1
Asphyxia
Placenta and cord
Maternal condition
Sudden Infant Death Syndrome
Unknown or Other
Total
Mortality Type
Fetal deaths
No.
%
71
30.0
102
43.0
***
3.8
***
0.4
54
22.8
237
100.0
Neonatal deaths
No.
%
14
29.2
20
41.7
8
16.7
6
12.5
48
100.0
Extracted from the Perinatal Mortality Database 7 January 2015.
1
Any infant without malformation that died and had birthweight less than 1000 grams is reported in the
“extremely low birthweight” category
107
Western Australia’s Mothers and Babies 2012, 30th Annual Report
6. References
AIHW. Indigenous identification in hospital separations data - Quality report. Canberra:
Australian Institute of Health and Welfare, 2013.
—. Metadata Online Registry (METeOR) for the Perinatal National Minimum Data Set
2010-2011. 2 December 2009.
http://meteor.aihw.gov.au/content/index.phtml/itemId/363256 (accessed March
28, 2014).
Dobbins, TA, EA Sullivan, CL Roberts, and JM Simpson. “Australian national
birthweight percentiles by sex and gestation age, 1998-2007.” MJA 197, no. 5
(2012): 291-294.
DoHA. What is a Healthy Weight. Edited by Department of Health Australia. 02 April
2009.
http://www.health.gov.au/internet/healthyactive/publishing.nsf/Content/healthyweight (accessed July 23, 2014).
Downey, F. A validation study of the Western Australian Midwives’ Notification System,
2005 data. Statistical Series Number 78, Health Information Centre, Department
of Health, WA, Perth: Department of Health, 2007.
Hilder, L, Z Zhichao, M Parker, S Jahan, and GM Chambers. Australia's mothers and
babies 2012. Perinatal statistics series no. 30. Cat. no. PER 69, Canberra:
AIHW, 2014.
Hutchinson, M, A Joyce, and M Cheong. Induced Abortions in Western Australia 20102012. Perth: Department of Health, WA, 2013.
Tough, SC, C Newburn-Cook, DW Johnston, LW Svenson, S Rose, and Belik. “Delayed
childbearing and its impact on population rate changes in lower birth weight,
multiple birth, and preterm delivery.” Pediatrics, 109, 2002: 399-403.
Young, M. Assessing the Quality of Identification of Aboriginal and Torres Strait Islander
People in Western Australia Hospital Data, 2000. Occassional Paper 13, ISSN
13297252, Health Information Centre, Department of Health, WA, Perth:
Department of Health, 2001.
108
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Appendix A: Glossary
Age-specific birth rate
The total births (live births and still births) per 1000 born to
women aged between 15–44 years.
Anaesthesia
Often administered immediately before delivery and differs from
analgesia in that it causes a loss of all sensation. It includes
loss of touch, loss of certain reflexes and loss of ability to move.
With general anaesthesia there is also a loss of consciousness.
Analgesia
Often administered during labour to reduce the feeling of pain
while allowing sensations of touch, pressure and the ability to
move to generally remain intact.
Apgar score
A numerical scoring system applied after birth to evaluate the
condition of the infant. It is based on heart rate, respiration,
muscle tone, reflexes and colour. A low score indicates poor
condition of the infant.
Augmentation of labour
Refers to the use of medication or other intervention to ‘speed
up' the process of labour that has already commenced
spontaneously. Augmentation may be required to assist with an
abnormal or difficult labour (dystocia), or to speed up normal
labour if the health of the mother or baby is at risk.
Body Mass Index (BMI)
The calculation for BMI was maternal weight (kgs) divided by
the maternal height (m) squared, for example 72kgs/1.65m2 is
26.45 BMI.
Where height and weight at time of booking for pregnancy care
was reported. However, if the woman had no weight recorded
before 20 weeks gestation, it will be the self-reported weight at
conception.
Born before arrival (BBA)
A birth that occurs prior to arrival of the mother at the health
service reporting the birth. It usually indicates a planned
hospital or birth centre birth occurring unexpectedly before
arrival at service. A planned homebirth is reported as BBA if
birth occurs before midwife arrives at the home. BBA is an
indication of a birth occurring in an uncontrolled environment.
Birth defects
Any defect present in the infant at the time of birth, probably of
developmental origin.
Birthweight
The first weight, measured of the infant, to the nearest five
grams. Usually obtained within the first hour of birth.
Caesarean section
Infant is born through an incision in the maternal uterus via the
abdomen.
Elective caesarean section: a scheduled procedure that occurs
prior to onset of labour and rupture of membranes and without
any labour induction procedure.
Emergency caesarean section: a procedure performed at a time
determined by an arising complication. May be performed
before or after the onset of labour.
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Western Australia’s Mothers and Babies 2012, 30th Annual Report
Diabetes
Two values are reported to the Midwives Notification System,
“gestational diabetes” as a pregnancy complication and “preexisting diabetes” as a medical condition. Pre-existing diabetes
includes both Type 1 and Type 2 diabetes.
Crude birth rate
The number of liveborn infants occurring per 1000 of the total
population.
Epidural
Injection of analgesic agent outside the dura mater encasing
the maternal spinal canal.
Episiotomy
An incision of the perineum and vagina to enlarge the opening
of the vagina.
Gestational age
The duration of pregnancy from the first day of the last normal
menstrual period. If unable to be determined in this way,
ultrasound estimations of gestational age during pregnancy or
assessment of the newborn infant may be used to determine
this age. Data presented here is in completed weeks e.g. a
gestational age of 40 days would be presented as 5 weeks and
not 5 weeks and 5 days or 6 weeks.
Health Service Area
Within WA, there are three Health Service Areas created by
grouping of the Statistical Local Areas (SLA) devised by the
Australian Bureau of Statistics (ABS) into North Metro, South
Metro and Country.
Statistical Local Area
(SLA) An Australian Standard Geographical Classification
(ASGC) defined area that comprises a suburb or groups of
suburb. Describes geographical locations for the whole of
Australia without gaps or overlays. It is described with a 9 digit
number made up of values representing state, statistical
division (SD), statistical subdivision (SSD) and SLA, for
example, the SLA of Armadale (City) has an SLA value of
505250210 which can be broken down to 5/05/25/0210 to
represent values for WA/SD/SSD/SLA.
Health Region
SLAs also determine division of the Country Area into the seven
Regions of Kimberley, Pilbara, Midwest, Wheatbelt, Goldfields,
Southwest, and Great Southern. With the two undivided
Metropolitan Areas of North and South, these comprise the nine
Health Regions in WA.
Homebirth
Homebirths reported in the annual report only include women
attended by midwives for a planned homebirth. Other
homebirths may include “freebirths”, a homebirth planned to
occur without a health professional in attendance, or an
unplanned or unexpected homebirth where the birth may be
reported as "born before arrival" to the health service.
Induction of labour
The process of using medications or procedures to artificially
initiate labour. Induction is performed when birth in next 24
hours was believed to best serve the welfare of mother and/or
infant.
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Western Australia’s Mothers and Babies 2012, 30th Annual Report
Length of stay
The total number of days spent in hospital. A stay of less than
one day (admission, birth and discharge occur on the same
day) is counted as one day, in the total days of care. For
women or infants admitted and discharged on different days,
the number of days is computed by subtracting the date of
admission/birth from the day of separation. For planned home
births length of stay is reported as 0 days from date of birth.
Livebirth
The complete expulsion or extraction from its mother of an
infant irrespective of duration of pregnancy, which after birth
shows signs of life.
Mortality rates
Fetal death rate: the number of fetal deaths per 1000 total births
in a year.
Neonatal mortality: the number of neonatal deaths per 1000 live
births in a year.
Perinatal mortality: the number of stillbirths and neonatal deaths
per 1000 total births in a year.
Neonatal death
The death of a liveborn infant within 28 days of birth.
Obstetrician
Medical Practitioner who has achieved consultant status in
Obstetrics and Gynaecology.
Other medical officer
Medical Practitioner who is not a consultant of Obstetrics and
Gynaecology.
Oxytocin/Syntocinon
Oxytocin is a naturally occurring hormone released by the
pituitary gland. Two of its actions are to stimulate smooth
muscle of the uterus producing rhythmic contractions and cause
contraction of small muscles in the breast facilitating lactation.
Syntocinon is a synthetic copy of Oxytocin made available by
pharmaceutical companies as an injectable solution.
Parity
The total number of infants born alive or stillborn to the mother
prior to the index pregnancy.
Nulliparous:
Never having completed a pregnancy
beyond 20 weeks gestation prior to the index pregnancy.
Multiparous: having completed one or more pregnancies
beyond 20 weeks gestation.
Perinatal death
A stillbirth (fetal death) or neonatal death.
Perineal status
First degree tear: a perineal graze, laceration, or tear involving
the fourchette, hymen, labia, skin, vagina or vulva.
Second degree tear: a perineal laceration or tear involving the
pelvic floor or perineal muscles or vagina muscles.
Third degree tear: a perineal laceration or tear involving the
anal sphincter or rectovaginal septum.
Fourth degree tear: a third degree perineal laceration or tear
which also involves the anal or rectal mucosa.
Plurality
The number of infants resulting from a pregnancy of 20 weeks
gestation or more. On this basis a birth may be classified as
single or multiple.
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Western Australia’s Mothers and Babies 2012, 30th Annual Report
Prostaglandin
Prostaglandins are naturally occurring products of metabolism.
Some cause strong contraction of the uterine muscle and
ripening and dilatation of the cervix. Prostaglandin E formulas
are synthetic copies made available by pharmaceutical
companies in formats that can be administered orally,
sublingually or vaginally.
Relative Risk (RR)
The likelihood of having an adverse event following exposure to
some factor. Determines association rather than causation.
Calculation used to describe Relative Risk (RR) in this report,
was the Rate Ratio (rate of occurrence in exposed) / (rate of
occurrence in non-exposed). For example (number of infants of
Aboriginal mothers with low birthweight/number of infants of
Aboriginal Mother) / (number of infants of non-Aboriginal
mothers with low birthweight/number of infants born to nonAboriginal mothers)
SEIFA Disadvantage Index
Using 2011 census data, Statistical Area 2 (SA2) values
were allocated to five groups based on the socio-economicindex-for-areas (SEIFA 2012) disadvantage index. Group I is
considered as having the highest disadvantage and group V
has the lowest disadvantage.
http://www.abs.gov.au/AUSSTATS/[email protected]/Lookup/2033.0.55
.001Main+Features12012?OpenDocument.
Stillbirth or Fetal death
The complete expulsion or extraction from its mother of an
infant which did not show any sign of life from the time of birth.
Where the pregnancy was at least 20 weeks gestation or the
infant’s birthweight is at least 400 grams.
Term Infants
Infants born from pregnancy with gestational age of 37 weeks
or greater.
Vertex Presentation
The most common presentation of the fetus immediately prior to
birth. The fetal chin is tucked in and the smallest and roundest
circumference of the fetal head (just above the ears) is applied
to the maternal cervix.
112
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Appendix B: Supplementary Tables
Table 113: Trend for age-specific birth rates and Aboriginal status for women
who gave birth in WA, 1983-2012
Aboriginal Status of mother
Year of
birth
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Aboriginal
15–19
161.4
164.0
158.4
145.8
144.9
164.6
149.1
149.6
162.1
145.5
150.4
151.4
133.6
125.9
135.4
130.6
125.2
122.6
112.9
110.5
111.2
109.7
121.2
118.0
105.0
104.0
98.2
91.0
93.5
86.8
20–34
134.4
130.3
137.6
135.9
144.4
146.8
148.0
157.6
138.3
135.4
132.9
129.8
133.7
130.1
140.7
130.9
140.0
136.9
142.4
142.6
127.9
129.8
138.9
150.4
150.0
138.8
140.2
133.1
133.9
122.7
Total
Non-Aboriginal
35–44
15.5
20.0
13.7
15.2
19.6
15.8
17.5
19.3
17.1
15.4
17.0
14.5
18.3
18.1
18.8
23.3
25.2
24.8
21.0
26.2
22.2
24.7
27.7
26.6
33.6
29.5
30.0
28.1
25.9
27.5
15–19
21.6
20.3
18.3
19.4
18.0
19.0
18.8
20.1
19.6
20.0
18.8
20.3
19.8
19.6
17.8
18.8
18.4
17.2
16.2
16.3
14.5
15.1
15.7
16.1
16.3
16.2
15.2
13.8
13.9
13.5
20–34
112.8
111.1
110.7
109.5
108.3
108.7
107.4
106.7
101.4
101.5
101.3
100.2
98.7
97.9
95.0
95.6
95.9
93.3
91.2
90.4
88.9
91.1
93.5
97.0
99.9
98.2
95.5
93.5
91.5
94.5
35–44
14.5
14.4
16.0
16.8
16.6
18.3
18.4
19.4
19.0
20.3
21.3
22.3
23.3
24.3
24.8
26.6
26.5
26.9
27.5
27.4
29.4
30.9
34.4
37.9
39.9
41.2
39.7
39.9
39.7
40.3
15–19
27.6
26.7
24.7
25.1
23.6
25.5
24.5
25.7
25.9
25.6
24.5
26.0
24.7
24.4
23.1
24.0
23.4
22.2
20.9
20.9
19.2
19.9
21.0
21.3
20.9
20.7
19.4
17.8
18.1
17.4
20–34
113.4
111.7
111.6
110.3
109.5
110.0
108.8
108.4
102.7
102.7
102.4
101.3
100.1
99.1
96.8
97.0
97.6
95.1
93.2
92.5
90.5
92.6
95.3
99.1
101.8
99.7
97.2
95.0
93.0
95.5
35–44
14.5
14.5
16.0
16.7
16.7
18.3
18.4
19.4
18.9
20.2
21.2
22.1
23.2
24.1
24.7
26.5
26.5
26.8
27.3
27.3
29.2
30.7
34.2
37.5
39.8
40.9
39.4
39.5
39.3
40.0
Data Extracted from Midwives’ Notification System on 20 June 2014.
The 15-19 year age group includes births to mothers younger than 15 years of age. The 40-45 year age group includes births to
mothers aged 45 years or more.
Age-Specific Birth Rate was from the total number of births in one year per 1000 women of the same age group.
No population data available for years 1980 to 1982.
Projected population data were used to calculate rates for 2012.
113
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 114: Trend for Aboriginal status for women who gave birth in WA, 19802012
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Maternal Aboriginal Status
Aboriginal
non-Aboriginal
No.
%
No.
%
1030
5.0
19580
1110
5.0
20871
1123
5.1
21029
1142
5.0
21684
1185
5.2
21518
1247
5.4
21829
1239
5.2
22364
1336
5.6
22559
1436
5.8
23366
1439
5.7
23718
1548
6.0
24154
1468
5.9
23211
1422
5.7
23548
1442
5.8
23531
1439
5.7
23632
1455
5.8
23633
1431
5.7
23761
1564
6.3
23304
1508
6.0
23784
1600
6.3
23777
1597
6.4
23220
1627
6.6
22868
1652
6.8
22745
1527
6.3
22748
1556
6.2
23557
1698
6.4
24828
1788
6.3
26466
1805
6.1
27826
1722
5.7
28515
1749
5.7
29011
1683
5.5
29160
1723
5.4
30011
1630
4.9
31763
95.0
95.0
94.9
95.0
94.8
94.6
94.8
94.4
94.2
94.3
94.0
94.1
94.3
94.2
94.3
94.2
94.3
93.7
94.0
93.7
93.6
93.4
93.2
93.7
93.8
93.6
93.7
93.9
94.3
94.3
94.5
94.6
95.1
Total
No.
20610
21981
22152
22826
22703
23076
23603
23895
24802
25157
25702
24679
24970
24973
25071
25088
25192
24868
25292
25377
24817
24495
24397
24275
25113
26526
28254
29631
30237
30760
30843
31734
33393
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
114
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 115: Trend for place of birth for women who gave birth in WA, 1980-2012
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Tertiary
No.
%
5126
24.9
5332
24.3
5249
23.7
4731
20.7
4894
21.6
4666
20.2
4921
20.8
4625
19.4
4768
19.2
4675
18.6
4677
18.2
4200
17.0
4301
17.2
4695
18.8
4917
19.6
4930
19.7
5074
20.1
5025
20.2
4912
19.4
5150
20.3
4671
18.8
4168
17.0
4267
17.5
4335
17.9
4425
17.6
4811
18.1
5792
20.5
6008
20.3
6051
20.0
5653
18.4
5744
18.6
5650
17.8
5900
17.7
Place of Birth
Public
Private
Home Birth
BBA
No.
%
No.
%
No.
%
No. %
10935 53.1
4436 21.5
62 0.3
50 0.2
11994 54.6
4521 20.6
59 0.3
75 0.3
11362 51.3
5374 24.3
94 0.4
73 0.3
11872 52.0
6065 26.6
99 0.4
59 0.3
11236 49.5
6411 28.2
96 0.4
66 0.3
11296 49.0
6900 29.9
143 0.6
71 0.3
11977 50.7
6483 27.5
174 0.7
48 0.2
12008 50.3
7053 29.5
144 0.6
65 0.3
12360 49.8
7420 29.9
175 0.7
79 0.3
12751 50.7
7478 29.7
176 0.7
77 0.3
13346 51.9
7436 28.9
151 0.6
92 0.4
13052 52.9
7204 29.2
145 0.6
77 0.3
13267 53.1
7216 28.9
107 0.4
78 0.3
12934 51.8
7161 28.7
102 0.4
81 0.3
12841 51.2
7111 28.4
109 0.4
93 0.4
12912 51.5
7055 28.1
96 0.4
95 0.4
12332 49.0
7583 30.1
120 0.5
84 0.3
11925 48.0
7741 31.1
112 0.5
65 0.3
11979 47.4
8200 32.4
101 0.4 100 0.4
11634 45.8
8397 33.1
123 0.5
73 0.3
11312 45.6
8633 34.8
120 0.5
81 0.3
10787 44.0
9316 38.0
137 0.6
87 0.4
10279 42.1
9645 39.5
120 0.5
85 0.3
9971 41.1
9726 40.1
163 0.7
80 0.3
10325 41.1 10131 40.3
149 0.6
82 0.3
10949 41.3 10517 39.6
150 0.6
98 0.4
11164 39.5 10997 38.9
194 0.7 107 0.4
11363 38.4 11928 40.3
203 0.7 127 0.4
11633 38.5 12186 40.3
232 0.8 129 0.4
12231 39.8 12493 40.6
245 0.8 126 0.4
12168 39.5 12539 40.7
255 0.8 129 0.4
12993 40.9 12733 40.1
232 0.7 126 0.4
13492 40.4 13673 40.9
200 0.6 128 0.4
Total
No.
20609
21981
22152
22826
22703
23076
23603
23895
24802
25157
25702
24678
24969
24973
25071
25088
25193
24868
25292
25377
24817
24495
24396
24275
25112
26525
28254
29629
30231
30748
30835
31734
33393
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
BBA indicates women who give birth before arrival at the health service or for homebirths before the midwife arrived at the home.
Homebirth total includes both public and private homebirths and public births at the freestanding birth centre in Kalamunda.
Tertiary total includes women giving birth at the Birth Centre attached.
115
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 116: Trend for smoking tobacco during pregnancy in women who gave
birth in WA, 1999-2012
Year
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Smoking in pregnancy
Smoking
Non-smoking
No.
%
No.
%
5737
22.6
19640
77.4
5260
21.2
19557
78.8
5255
21.5
19240
78.5
4932
20.2
19464
79.8
4584
18.9
19691
81.1
4307
17.2
20805
82.8
4523
17.1
22002
82.9
4941
17.5
23313
82.5
4885
16.5
24744
83.5
4660
15.4
25571
84.6
4453
14.5
26295
85.5
3710
12.0
27125
88.0
3826
12.1
27908
87.9
3863
11.6
29530
88.4
Total
No.
25377
24817
24495
24396
24275
25112
26525
28254
29629
30231
30748
30835
31734
33393
Extracted from Midwives’ Notification System on 20 June 2014.
Data collection commenced 1999.
116
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 117: Trend for number of previous infants for women who gave birth in WA,
1980-2012
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Number of Previous Infants
0
1-2
3-4
≥5
%
%
%
%
39.1
50.8
8.4
39.2
51.0
8.4
39.6
50.7
8.5
39.3
51.2
8.2
38.7
51.7
8.3
38.1
52.2
8.4
38.9
51.4
8.5
38.9
51.3
8.5
38.6
51.4
8.7
39.5
50.2
8.9
39.0
50.5
9.2
39.7
49.8
9.1
38.7
50.8
9.0
38.7
50.9
8.9
40.0
49.7
8.8
40.6
49.2
8.6
40.0
49.9
8.5
40.3
49.6
8.6
40.0
49.7
8.7
40.4
49.6
8.4
41.2
48.5
8.5
40.7
49.4
8.2
40.6
49.3
8.4
41.3
49.0
7.8
41.9
48.6
7.8
41.9
48.4
7.8
41.8
48.2
8.0
42.0
48.5
7.6
41.3
49.0
7.9
41.9
48.8
7.5
42.4
48.5
7.4
42.5
49.2
6.6
42.9
48.8
6.8
Total Women
1.7
1.3
1.2
1.3
1.3
1.2
1.2
1.3
1.3
1.4
1.3
1.3
1.5
1.6
1.5
1.6
1.5
1.6
1.6
1.6
1.9
1.8
1.8
1.9
1.8
1.9
2.0
2.0
1.8
1.7
1.8
1.7
1.6
18786
21981
22152
22826
22703
23076
23603
23895
24802
25157
25702
24678
24969
24973
25071
25088
25193
24868
25292
25377
24817
24495
24396
24275
25112
26525
28254
29629
30231
30748
30835
31734
33393
Extracted from Midwives’ Notification System on 20 June 2014.
117
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 118: Trend for onset of labour for women who gave birth in WA, 1986-2012
Year
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Spontaneous
No.
%
14956
63.4
15092
63.2
15826
63.8
15923
63.3
16638
64.7
15815
64.1
15537
62.2
14997
60.1
15092
60.2
15024
59.9
14985
59.5
14428
58.0
14186
56.1
14181
55.9
13745
55.4
12830
52.4
12535
51.4
12266
50.5
12680
50.5
13091
49.4
14424
51.1
15497
52.3
15909
52.6
16020
52.1
15811
51.3
16260
51.2
16717
50.1
Onset of Labour
Induction
No.
%
6363 27.0
6277 26.3
6428 25.9
6487 25.8
6180 24.0
6135 24.9
6544 26.2
6872 27.5
6876 27.4
6988 27.9
7036 27.9
7046 28.3
7394 29.2
7552 29.8
7266 29.3
7449 30.4
7314 30.0
7090 29.2
7210 28.7
7617 28.7
7873 27.9
8157 27.5
8058 26.7
8606 28.0
8788 28.5
9068 28.6
9720 29.1
No Labour
No.
%
2284
9.7
2526 10.6
2548 10.3
2747 10.9
2884 11.2
2728 11.1
2888 11.6
3104 12.4
3103 12.4
3076 12.3
3172 12.6
3394 13.6
3712 14.7
3644 14.4
3806 15.3
4216 17.2
4547 18.6
4919 20.3
5222 20.8
5817 21.9
5957 21.1
5975 20.2
6264 20.7
6122 19.9
6236 20.2
6406 20.2
6956 20.8
Total
No.
%
23603 100.0
23895 100.0
24802 100.0
25157 100.0
25702 100.0
24678 100.0
24969 100.0
24973 100.0
25071 100.0
25088 100.0
25193 100.0
24868 100.0
25292 100.0
25377 100.0
24817 100.0
24495 100.0
24396 100.0
24275 100.0
25112 100.0
26525 100.0
28254 100.0
29629 100.0
30231 100.0
30748 100.0
30835 100.0
31734 100.0
33393 100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Data collection commenced 1986.
118
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 119: Trend for method of birth for women who gave birth in WA, 1980-2012
Year
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
Spontaneous
Vertex
No.
%
13572
65.9
14471
65.8
14191
64.1
14453
63.3
14315
63.1
14452
62.6
14944
63.3
15135
63.3
16161
65.2
16133
64.1
16444
64.0
15963
64.7
16027
64.2
15873
63.6
15935
63.6
16207
64.6
16120
64.0
15755
63.4
15792
62.4
15772
62.2
15095
60.8
14618
59.7
14137
57.9
13832
57.0
13751
54.8
14177
53.4
15373
54.4
15918
53.7
15895
52.6
16032
52.1
15961
51.8
16195
51.0
16680
50.0
Method of Birth
Assisted
Elective
Breech
Vaginal
Caesarean
No.
%
No.
%
No.
%
4373
21.2 358 1.7 1096
5.3
4642
21.1 286 1.3 1250
5.7
4820
21.8 370 1.7 1406
6.3
4972
21.8 376 1.6 1488
6.5
4923
21.7 324 1.4 1560
6.9
4813
20.9 317 1.4 1804
7.8
4675
19.8 298 1.3 1851
7.8
4466
18.7 264 1.1 2063
8.6
4201
16.9 246 1.0 2198
8.9
4231
16.8 252 1.0 2357
9.4
4216
16.4 208 0.8 2493
9.7
3974
16.1 193 0.8 2361
9.6
3943
15.8 186 0.7 2559
10.2
3728
14.9 150 0.6 2763
11.1
3738
14.9 175 0.7 2729
10.9
3672
14.6 151 0.6 2740
10.9
3781
15.0 144 0.6 2865
11.4
3535
14.2 122 0.5 3042
12.2
3449
13.6 145 0.6 3270
12.9
3529
13.9 148 0.6 3310
13.0
3300
13.3 142 0.6 3520
14.2
2998
12.2 113 0.5 3744
15.3
2999
12.3
94 0.4 4004
16.4
2830
11.7 109 0.4 4326
17.8
3143
12.5
90 0.4 4537
18.1
3260
12.3 100 0.4 5067
19.1
3548
12.6
97 0.3 5276
18.7
3907
13.2 111 0.4 5289
17.9
4135
13.7 136 0.4 5485
18.1
4353
14.2 127 0.4 5299
17.2
4410
14.3 107 0.3 5375
17.4
4646
14.6 127 0.4 5472
17.2
5040
15.1 132 0.4 5969
17.9
Emergency
Caesarean
No.
%
1205
5.8
1332
6.1
1365
6.2
1537
6.7
1581
7.0
1690
7.3
1835
7.8
1967
8.2
1996
8.0
2184
8.7
2338
9.1
2187
8.9
2254
9.0
2459
9.8
2494
9.9
2318
9.2
2283
9.1
2414
9.7
2636
10.4
2618
10.3
2760
11.1
3022
12.3
3162
13.0
3178
13.1
3591
14.3
3921
14.8
3960
14.0
4404
14.9
4580
15.2
4937
16.1
4982
16.2
5294
16.7
5572
16.7
Total
No.
20609
21981
22152
22826
22703
23076
23603
23895
24802
25157
25702
24678
24969
24973
25071
25088
25193
24868
25292
25377
24817
24495
24396
24275
25112
26525
28254
29629
30231
30748
30835
31734
33393
%
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Extracted from Midwives’ Notification System on 20 June 2014.
Method of birth for women with multiple births was determined using method of birth of first infant born.
119
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Table 120: Trend for gender of infants born in WA, 1980-2012
Year
1980
1981
1982
1983
1984
1985
1986*
1987*
1988*
1989
1990*
1991
1992*
1993*
1994*
1995*
1996*
1997*
1998
1999
2000
2001
2002
2003
2004
2005
2006*
2007
2008*
2009*
2010*
2011*
2012*
Male
No.
10671
11580
11473
11975
11860
11928
12345
12477
12970
13041
13416
12775
13073
13101
13014
13137
13192
13034
13095
13147
12768
12836
12617
12625
13059
13761
14490
15459
15634
16062
15935
16563
17393
Gender of birth
Female
%
No.
%
51.3
10143
48.7
52.1
10641
47.9
51.2
10918
48.8
51.9
11097
48.1
51.6
11103
48.4
51.1
11429
48.9
51.7
11541
48.3
51.5
11726
48.4
51.6
12185
48.4
51.1
12502
48.9
51.6
12602
48.4
51.1
12233
48.9
51.6
12248
48.4
51.7
12233
48.3
51.2
12403
48.8
51.6
12302
48.3
51.6
12390
48.4
51.6
12231
48.4
51.0
12583
49.0
51.0
12623
49.0
50.6
12460
49.4
51.5
12105
48.5
50.9
12167
49.1
51.2
12052
48.8
51.2
12470
48.8
51.0
13217
49.0
50.5
14173
49.4
51.4
14614
48.6
51.0
15032
49.0
51.5
15144
48.5
51.0
15320
49.0
51.5
15623
48.5
51.4
16461
48.6
Extracted from Midwives’ Notification System on 20 June 2014.
Values <5 are suppressed by not displaying infants of indeterminate gender nor totals of infants born each year.
* indicate years where there were infants of indeterminate gender born.
120
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Appendix C: Notification of case attended form Jan-Jun 2012
121
Western Australia’s Mothers and Babies 2012, 30th Annual Report
Appendix C: Notification of case attended form Jul-Dec 2012
122
Western Australia’s Mothers and Babies 2012, 30th Annual Report
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