National Perinatal Data Collection Research Articles

Time trends, projections, and spatial distribution of low birthweight in Australia, 2009-2030: Evidence from the National Perinatal Data Collection.

Infants with low birthweight (LBW, birthweight <2500 g) have increased in many high-resource countries over the past two decades. This study aimed to investigate the time trends, projections, and spatial distribution of LBW in Australia, 2009-2030. We used standard aggregate data on 3 346 808 births from 2009 to 2019 from Australia's National Perinatal Data Collection. Bayesian linear regression model was used to estimate the trends in the prevalence of LBW in Australia. Wefound that the prevalence of LBW was 6.18% in 2009, which has increased to 6.64% in 2019 (average annual rate of change, AARC=+0.76%). If the national trend remains the same, the projected prevalence of LBW in Australia will increase to 7.34% (95% uncertainty interval, UI=6.99, 7.68) in 2030. Observing AARC across different subpopulations, the trend of LBW was stable among Indigenous mothers, whereas it increased among non-Indigenous mothers (AARC=+0.81%). There is also an increase among the most disadvantaged mothers (AARC=+1.08%), birthing people in either of two extreme age groups (AARC=+1.99% and +1.53% for <20 years and ≥40 years, respectively), and mothers who smoked during pregnancy (AARC=+1.52%). Spatiotemporal maps showed that some of the Statistical Area level 3 (SA3) in Northern Territory and Queensland had consistently higher prevalence for LBW than the national average from 2014 to 2019. Overall, the prevalence of LBW has increased in Australia during 2009-2019; however, the trends vary across different subpopulations. If trends persist, Australia will not achieve the Sustainable Development Goals (SDGs) target of a 30% reduction in LBW by 2030. Centering and supporting the most vulnerable subpopulations is vital to progress the SDGs and improves perinatal and infant health in Australia.

Screening for adverse childhood experiences in antenatal care settings: A scoping review.

Adverse childhood experiences (ACEs) are associated with many health problems in women during pregnancy, including depression/anxiety, gestational diabetes and adverse birth outcomes. However, unlike other health risk factors, screening for ACEs has not been widely implemented in antenatal care settings. The aim of the scoping review was to explore the challenges in screening for ACEs in antenatal care settings and to provide the lessons learnt and evidence that guide the practice of ACE screening for both healthcare providers and pregnant women. A five-stage process for conducting the scoping review was utilised. Searches of four key databases (PubMed, PsycINFO, CINAHL and SCOPUS) and reference lists from relevant studies were conducted. Seven publications met the inclusion criteria. Challenges identified for healthcare providers in screening for ACEs include lack of knowledge and confidence in ACE tool and shortage of time and resources to undertake screening. Impediments for pregnant women include concerns about privacy. However, there were examples of effective practice for ACE screening in antenatal care settings that could apply widely. Addressing impediments to ACE screening is critical in implementing trauma-informed practices that can identify women at risk of adverse health outcomes during pregnancy. A study on screening for ACEs in antenatal care in both public and private settings is needed to examine its feasibility and acceptability in the Australian context before being included in the National Perinatal Data Collection.

Sex ratios at birth in Australia according to mother's country of birth: A national study of all 5 614 847 reported live births 1997-2016.

ObjectivesSon preference and sex selective practices have resulted in a deficit of girls in several countries, primarily across Asia. Emerging evidence indicates that son preference survives migration to Western high-income countries. The objective of this study was to assess male-to-female (M/F) ratios at birth per mother’s country of birth in Australia 1997–2016, in total and by parity, and by states/territories and over time.MethodsData for this national population-based cross-sectional study were obtained from the National Perinatal Data Collection (NPDC) and included all live births in Australia 1997–2016 (N = 5 614 847). M/F ratios with 95% Confidence Intervals were estimated.ResultsThe M/F ratio for births to Australian-born mothers was within the expected range (1.03–1.07) regardless of parity and time period. M/F ratios were elevated above the expected range for births to mothers born in China in the total sample (M/F ratio 1.084, 95% confidence interval 1.071–1.097) and at parity 2 (1.175, 1.120–1.231), and for births to mothers born in India at parity 2 (1.146, 1.090–1.204). Parity 2 births were the most consistently male-biased across time. Across states, elevated M/F ratios were identified for both groups in New South Wales (China parity 2: 1.182, 1.108–1.260; India parity 2: 1.182, 1.088–1.285), for births to Chinese-born mothers in Victoria (total births: 1.097, 1.072–1.123; parity 1: 1.115, 1.072–1.159) and Australian Capital Territory (total births: 1.189, 1.085–1.302) and births to Indian-born mothers Western Australia (parity 2: 1.307, 1.122–1.523).ConclusionsSon preference persists in some immigrant communities after migration to Australia. The consistent pattern of elevated M/F ratios across the larger states indicates that sex imbalances at birth are largely independent of restrictiveness of local abortion laws. Drivers and consequences of son preference in Western high-income settings should be explored to further promote gender equality, and to strengthen support for women who may be vulnerable to reproductive coercion.

New Australian birthweight centiles.

To prepare more accurate population-based Australian birthweight centile charts by using the most recent population data available and by excluding pre-term deliveries by obstetric intervention of small for gestational age babies. Population-based retrospective observational study. Australian Institute of Health and Welfare National Perinatal Data Collection. All singleton births in Australia of 23-42 completed weeks' gestation and with spontaneous onset of labour, 2004-2013. Births initiated by obstetric intervention were excluded to minimise the influence of decisions to deliver small for gestational age babies before term. Birthweight centile curves, by gestational age and sex. Gestational age, birthweight, sex, and labour onset data were available for 2807051 singleton live births; onset of labour was spontaneous for 1582137 births (56.4%). At pre-term gestational ages, the 10th centile was higher than the corresponding centile in previous Australian birthweight charts based upon all births. Current birthweight centile charts probably underestimate the incidence of intra-uterine growth restriction because obstetric interventions for delivering pre-term small for gestational age babies depress the curves at earlier gestational ages. Our curves circumvent this problem by excluding intervention-initiated births; they also incorporate more recent population data. These updated centile curves could facilitate more accurate diagnosis of small for gestational age babies in Australia.

Has Human Papillomavirus (HPV) Vaccination Prevented Adverse Pregnancy Outcomes? Population-Level Analysis After 8 Years of a National HPV Vaccination Program in Australia.

Human papillomavirus (HPV) infection, and its sequelae of precancerous cervical lesions and their subsequent treatment, have been linked with an increased risk of adverse pregnancy outcomes. Publicly funded HPV vaccination of female adolescents began in Australia in 2007 with initial catch-up to age 26 years. Using data from the National Perinatal Data Collection we compared rates of preterm births and small-for-gestational-age infants born in Australia 2000-2015. We used generalized linear models, assuming a Poisson distribution and log link function, with single-year categories of infant birth year, maternal age, and age-specific HPV vaccination coverage as independent variables. In maternal cohorts with 60%-80% HPV vaccination coverage as achieved in Australia, there was a relative rate reduction of 3.2% (95% confidence interval, 1.1%-5.3%) in preterm births and 9.8% (8.2% to 11.4%) in small-for-gestational-age infants, after adjustment for infant's birth year and maternal age. This analysis provides provisional population-level evidence of a reduction in adverse pregnancy outcomes in cohorts of women offered HPV vaccination. Confounding by smoking or other variables and/or ecological analysis limitations, however, cannot be excluded. These findings indicate potential broader benefits of HPV vaccination than have been documented to date.

Effects of prenatal maternal stress on birth outcomes following tropical cyclone Yasi in Queensland, Australia (2011)

Tropical cyclones cause widespread devastation while having a negative impact on human health and well-being. Maternal exposure to prenatal environmental stressors can lead to a shift in reproductive strategies. This study aims to statistically analyse maternal and infant health risks by studying birth outcomes following maternal prenatal exposure to tropical cyclone Yasi in Queensland, Australia. Queensland state birth records collected under the Australian National Perinatal Data Collection from January 2008 to December 2012 were analysed. A confounder controlled binary logistic regression model was used to statistically compare birth weight and gestation length in cyclone Yasi affected and unaffected Queensland local government areas (LGAs). Women in cyclone Yasi affected LGAs, had a significantly higher proportion (9.6%, p = 0.008) and significantly higher odds (OR = 1.26, 95% CI: 1.06 – 1.47) of having a preterm birth, compared to women in unaffected LGAs (7.9%). Women in affected LGAs during the year of cyclone Yasi (2011) also had a higher proportion of low birth weight births compared to women in the same LGAs during non-cyclone Yasi years (2008,2009,2010,2012). Our study supported a significant increase in the proportion of preterm births recorded for women pregnant in areas severely affected by cyclone Yasi. Our findings, and similar future research, will continue to inform the development of effective post-disaster perinatal health related policies and the continued improvement of disaster risk mitigation for vulnerable groups.

Gestational age-specific perinatal mortality rates for assisted reproductive technology (ART) and other births.

Is perinatal mortality rate higher among births born following assisted reproductive technology (ART) compared to non-ART births? Overall perinatal mortality rates in ART births was higher compared to non-ART births, but gestational age-specific perinatal mortality rate of ART births was lower for very preterm and moderate to late preterm births. Births born following ART are reported to have higher risk of adverse perinatal outcomes compared to non-ART births. This population-based retrospective cohort study included 407 368 babies (391 952 non-ART and 15 416 ART)-393 491 singletons and 10 877 twins or high order multiples. All births (≥20 weeks of gestation and/or ≥400 g of birthweight) in five states and territories in Australia during the period 2007-2009 were included in the study, using National Perinatal Data Collection (NPDC). Primary outcome measures were rates of stillbirth, neonatal and perinatal deaths. Adjusted odds ratio (AOR) and 95% confidence interval (CI) were used to estimate the likelihood of perinatal death. Rates of multiple birth and low birthweight were significantly higher in ART group compared to the non-ART group (P < 0.01). Overall perinatal mortality rate was significantly higher for ART births (16.5 per 1000 births, 95% CI 14.5-18.6), compared to non-ART births (11.3 per 1000 births, 95% CI 11.0-11.6) (AOR 1.45, 95% CI 1.26-1.68). However, gestational age-specific perinatal mortality rate of ART births (including both singletons and multiples) was lower for very preterm (<32 weeks' gestation) and moderate to late preterm births (32-36 weeks' gestation) (AOR 0.61, 95% CI 0.53-0.70 and AOR 0.61, 95% CI 0.53-0.70, respectively) compared to non-ART births. Congenital abnormality and spontaneous preterm were the most common causes of neonatal deaths in both ART and non-ART group. Due to different cut-off limit for perinatal period in Australia, the results of this study should be interpreted with cautions for other countries. Australian definition of perinatal period commences at 20 completed weeks (140 days) of gestation and ends 27 completed days after birth which is different from the definition by World Health Organisation (commences at 22 completed weeks (154 days) of gestation and ends seven completed days after birth) and by Centers for Disease Control and Prevention (includes infant deaths under age 7 days and fetal deaths at 28 weeks of gestation or more). Preterm birth is the single most important contributing factor to increased risk of perinatal mortality among ART singletons compared to non-ART singletons. Further research on reducing early preterm delivery, with the aim of reducing the perinatal mortality among ART births is needed. Couples who access ART treatment should be fully informed regarding the risk of preterm birth and subsequent risk of perinatal death. There was no funding associated with this study. No conflict of interest was declared.

Comparing alternative statistics on recent fertility trends in Australia

In recent years fertility statistics in the Australian Bureau of Statistics (ABS) publication Births, Australia have suffered from a number of issues, including delayed receipt of registration data from the Registrars and computer processing errors. They prompt questions about the quality of these statistics for measuring the level of fertility and its year-to-year changes. The aim of this paper is to compare three sets of fertility statistics, (1) ABS birth registrations, (2) ABS births by year of occurrence, and (3) births in the Australian Institute of Health and Welfare National Perinatal Data Collection (NPDC), at the national and state/territory scales. Annual births by state/territory of usual residence from the three data sources were obtained for the period 2004–2013 or 2004–2014. Recast Estimated Resident Populations from the ABS were used to calculate Total Fertility Rates. For some states and territories there are non-trivial differences in fertility as recorded by the three data sources. In Queensland the trend in fertility according to ABS birth registrations is quite different from that based on the NPDC; in Tasmania and the Northern Territory birth registrations exceed NPDC births by a notable margin. There appears to be more uncertainty about the levels and annual changes in Australian fertility than many users of the data may realise. All three fertility datasets seem to possess some limitations. It is suggested that a new Australian fertility database be created which employs data linkage to incorporate both birth registrations and perinatal data.

Australian national birthweight percentiles by sex and gestational age for twins, 2001-2010.

BackgroundBirthweight remains one of the strongest predictors of perinatal mortality and disability. Birthweight percentiles form a reference that allows the detection of neonates at higher risk of neonatal and postneonatal morbidity. The aim of the study is to present updated national birthweight percentiles by gestational age for male and female twins born in Australia.MethodsPopulation data were extracted from the Australian National Perinatal Data Collection for twins born in Australia between 2001 and 2010. A total of 43,833 women gave birth to 87,666 twins in Australia which were included in the study analysis. Implausible birthweights were excluded using Tukey’s methodology based on the interquartile range. Univariate analysis was used to examine the birthweight percentiles for liveborn twins born between 20 and 42 weeks gestation.ResultsBirthweight percentiles by gestational age were calculated for 85,925 live births (43,153 males and 42,706 females). Of these infants, 53.6 % were born preterm (birth before 37 completed weeks of gestation) while 50.2 % were low birthweight (<2500 g) and 8.7 % were very low birthweight (<1500 g). The mean birthweight decreased from 2462 g in 2001 to 2440 g in 2010 for male twins, compared with 2485 g in 1991–94. For female twins, the mean birthweight decreased from 2375 g in 2001 to 2338 g in 2010, compared with 2382 g in 1991–94.ConclusionsThe birthweight percentiles provide clinicians and researchers with up-to-date population norms of birthweight percentiles for twins in Australia.

Higher prevalence of pregnancy induced hypertension following assisted reproductive technology treatment

Given the higher proportion of women at older age accessing assisted reproductive technology (ART) and higher rate of multiple pregnancies after ART, it was suggested that ART is related with increased risk of pregnancy induced hypertension (PIH). The objective of this population study is to determine the association between ART and the prevalence of PIH controlling for age and plurality. A population cross-sectional study using National Perinatal Data Collection during 2007 and 2009 from five states in Australia. The study included 400392 mothers (3.6% of ART mothers) who gave births of ≥ 20 weeks of gestation or ≥ 400 grams of birthweight. Logistic regression was used to assess the association between ART and GD. Adjusted odds ratio (AOR) and 95% confidence intervals (CI) were calculated. The overall prevalence of PIH was 4.5%, with ART mothers having significantly higher prevalence of PIH (prevalence 6.9%) than non-ART mothers (4.5%). The prevalence of PIH was higher for mothers who had twins than those who had singletons (13.0% vs 6.1% for ART mothers, and 8.8% vs 4.4% for non-ART mothers). After controlling for age, parity, body mass index and other demographics, ART mothers had 24% increased odds of PIH compared to non-ART mothers (AOR 1.24, 95% CI 1.15-1.33). Of mothers who had singletons, ART mothers had 11% higher odds of PIH than non-ART mothers (AOR 1.11, 95% CI 1.02-1.20). Of mothers who had twins, ART mothers had 1.25 times higher odds of PIH than non-ART mothers (AOR 1.25, 95% CI 1.03-1.53). The 24% increased likelihood of PIH of ART mothers than non-ART mothers after controlling for co-existing risk factors indicates either factors associated with subfertility or the ART procedures may be associated with increased odds of PIH. The lower prevalence of PIH among singleton mothers compared to twins suggests that a policy of single embryo transfer may reduce the excess risk of PIH due to ART.

Higher prevalence of gestational diabetes mellitus following assisted reproduction technology treatment

Do mothers following assisted reproduction technology (ART) treatment have increased likelihood of gestational diabetes mellitus (GDM) compared with non-ART mothers after controlling for maternal factors and plurality? ART mothers had 28% increased likelihood of GDM compared with non-ART mothers. Advanced maternal age and multiple pregnancies are independently associated with increased likelihood of GDM. Given the average age of mothers having ART treatment is higher than non-ART mothers and the higher multiple pregnancy rate following ART treatment, ART treatment might be expected to be associated with increased risk of GDM. A population retrospective cohort study of 400 392 mothers who gave birth in Australia between 2007 and 2009, using the Australian National Perinatal Data Collection from five states (Australian Capital Territory, Queensland, Tasmania, Victoria and Western Australia) where a code for ART treatment is available. The study included 13 732 ART mothers and 386 660 non-ART mothers. The prevalence of GDM was compared between ART and non-ART mothers. Logistic regressions were used to assess the association between ART treatment and GDM. Odds ratio (OR), adjusted OR (AOR) and 95% confidence interval (CI) were calculated. A larger proportion of ART mothers were aged ≥40 years compared with non-ART counterpart (11.7 versus 3.4%, P < 0.01). The prevalence of GDM was 7.6% for ART mothers and 5.0% for non-ART mothers (P < 0.01). Mothers who had twins had higher prevalence of GDM than those who gave births to singletons (8.8 versus 7.5%, P = 0.06 for ART mothers; and 7.3 versus 5.0%, P < 0.01 for non-ART mothers). Overall, ART mothers had a 28% increased likelihood of GDM compared with non-ART mothers (AOR 1.28, 95% CI 1.20-1.37). Of mothers who had singletons, ART mothers had higher odds of GDM than non-ART mothers (AOR 1.26, 95% CI 1.18-1.36). There was no significant difference in the likelihood of GDM among mothers who had twins between ART and non-ART (AOR 1.18, 95% CI 0.94-1.48). For mothers aged <40 years, the younger the maternal age, the higher the odds of GDM for ART singleton mothers compared with non-ART singleton mothers. It was not possible to investigate which ART procedure is associated with increased risk of GDM and how the risk could have been minimized. The information on BMI and smoking during pregnancy was not stated for a large proportion of mothers. These limitations may have reduced the validity of the study. In agreement with other studies, our data suggest that the underlying cause of subfertility and some particular ART procedures might have played an important role in the increased likelihood of GDM. Together with the public education on not delaying motherhood, minimizing multiple pregnancies by applying single embryo transfer may diminish the excess risk of GDM related to ART treatment.

Assisted reproductive technology: public funding and the voluntary shift to single embryo transfer in Australia

To calculate cost savings to the Australian federal and state governments from the reduction in twin and triplet birth rates for infants conceived by assisted reproductive technology (ART) since 2002, and to determine the number of ART treatment programs theoretically funded by means of these savings. Costing model using data from the Australia and New Zealand Assisted Reproduction Database, the National Perinatal Data Collection and Medicare Australia on ART treatment cycles undertaken in Australia between 2002 and 2008. Annual savings in maternal and infant inpatient birth-admission costs resulting from the reduction in ART multiple birth rate; theoretical number of ART treatment programs funded and infants born by means of these savings. The reduction in the ART multiple birth rate from 18.8% in 2002 to 8.6% in 2008 resulted in estimated savings to government of $47.6 million in birth-admission costs alone. Theoretically, these savings funded 7042 ART treatment programs comprising one fresh plus one frozen embryo transfer cycle, equating to the birth of 2841 babies. Fifty-five per cent of the increased use of ART services since 2002 has been theoretically funded by the reduction in multiple birth infants. Against a backdrop of supportive public funding of ART in Australia, a voluntary shift to single embryo transfer by fertility clinicians and ART patients has resulted in substantial savings in hospital costs. Much of the growth in ART use has been theoretically cross-subsidised by the move to safer embryo transfer practices.

Smoking during pregnancy – need for consistent Public Health data in Australia

Maternal smoking remains one of the most common preventable causes of infant morbidity and mortality. In addition, pregnancy is a natural window for smoking cessation, and this has led to the suggestion that support for smoking cessation and relapse prevention needs to be as routine in antenatal care as the measurement of blood pressure. Quality Australian data documenting rates of tobacco consumption by women during various stages of pregnancy are not currently available. While there is a specification for perinatal data elements for mandatory collection and reporting at a national level, the Perinatal Minimum Data Set (NMDS) has no data element for smoking during pregnancy and there is no national agreement on collection of data on smoking during pregnancy. In Australia, five jurisdictions collect data on smoking during pregnancy; however, the definitions they use differ. The Australian Capital Territory and New South Wales use two questions – (1) did the mother smoke during pregnancy; (2) average number of cigarettes smoked per day during the second half of the pregnancy. Western Australia asks whether the mother smoked during pregnancy. South Australia collects data on – (1) smoking status at the first antenatal visit; (2) average number of tobacco cigarettes smoked per day in the second half of pregnancy. The Northern Territory has a question on smoking consumption at the first antenatal visit and at 36-weeks gestation. Given the different questions asked in the five jurisdictions, comparisons between states and territories are difficult and there is no national agreement. In Australia, the two main sources of data collection for smoking during pregnancy are the National Drug Strategy Household Survey (NDSHS) and the National Perinatal Data Collection (NPDC). Both have certain limitations when it comes to collecting data on smoking during pregnancy. The NDSHS (2007) asks about (1) self-reported smoking status in last 12 months when subjects were

Perinatal Outcomes of Women Intending to Give Birth in Birth Centers in Australia

A recent Australian study showed perinatal mortality was lower among women who gave birth in a birth center than in a comparable low-risk group of women who gave birth in a hospital. The current study used the same large population database to investigate whether perinatal outcomes were improved for women intending to give birth in a birth center at the onset of labor, regardless of the actual place of birth. Data were obtained from the National Perinatal Data Collection (NPDC) in Australia. The study included 822,955 mothers who gave birth during the 5-year period, 2001 to 2005, and their 836,919 babies. Of these, 22,222 women (2.7%) intended to give birth in a birth center at the onset of labor. Maternal and perinatal factors and outcomes were compared according to the intended place of birth. Data were not available on congenital anomalies, or cause, or timing of death. Women intending to give birth in a birth center at the onset of labor had lower rates of intervention and of adverse perinatal outcomes compared with women intending to give birth in a hospital, including less preterm birth and low birthweight. No statistically significant difference was found in perinatal mortality for term babies of mothers intending to give birth in a birth center compared with term babies of low-risk women intending to give birth in a hospital (1.3 per 1,000 births [99% CI = 0.66, 1.95] vs 1.7 per 1,000 births [99% CI = 1.50, 1.80], respectively). Term babies of women who intended to give birth in a birth center were less likely to be admitted to a neonatal intensive care unit or special care nursery, and no significant difference was found in other perinatal outcomes compared with term babies of low-risk women who intended to give birth in a hospital labor ward. Birth center care remains a viable option for eligible women giving birth at term.

Term breech singletons and caesarean section: A population study, Australia 1991–2005

To describe the method of birth of term breech singletons in Australia. A retrospective population-based study of women who gave birth to term breech singletons in Australia between 1 January 1991 and 31 December 2005 using data from the National Perinatal Data Collection. Caesarean section, vaginal breech birth. Method of birth changed for term breech singletons from 1991 (vaginal breech birth 23.1% versus caesarean (no labour 55.6%, labour 21.2%)) to 2005 (vaginal breech birth 3.7% versus caesarean (no labour 76.6%, labour 19.7%)). Overall, the population attributable risk percentage of term breech singletons for all caesarean sections declined from 10.2% in 1991 to 6.9% in 2005. Planned caesarean section is the standard method of birth for term breech singletons in Australia. Active measures including external cephalic version should be supported to reduce the rate of caesarean section where clinically indicated. Retention of a skilled clinical workforce is essential in the provision of the latter and to assist the minority of women having vaginal breech births. Breech presentation is not a major factor in the overall rise in caesarean section experienced by Australia since 1996.

Adverse outcomes of labour in public and private hospitals in Australia: a population‐based descriptive study

Almost all women in Australia have free access to public hospitals, where intrapar- tum care is usually provided by a mixture of midwives, junior medical officers, specialty trainees, and specialist obstetricians. In con- trast, women choosing to deliver in private hospitals have their care directly managed by specialist obstetricians. Compared with public hospitals, birth in Australian private hospitals is characterised by a higher rate of obstetric interventions such as induction of labour, episiotomy, instrumental delivery, ABSTRACT Objective: To compare the rate of serious adverse perinatal outcomes of term labour between private and public maternity hospitals in Australia. Design, setting and participants: A population-based study of 789 240 term singleton births in public and private hospitals in 2001-2004, using data from the National Perinatal Data Collection. Main outcome measures: Third- and fourth-degree perineal injury, requirement for high level of neonatal resuscitation, Apgar score < 7 at 5 minutes, admission to neonatal intensive care unit or special care nursery, and perinatal death. Results: 31.4% of the term singleton births occurred in private hospitals. After adjusting for maternal age, Indigenous status, parity, smoking status, diabetes, hypertension, remoteness of usual residence, and method of birth, the rates of all adverse outcomes studied were higher for public hospital births. For women, the adjusted odds ratio (AOR) for third- or fourth-degree perineal injury was 2.28 (95% CI, 2.16-2.40). For babies, the odds of a high level of resuscitation (AOR, 2.37; 95% CI, 2.17-2.59), low Apgar score (AOR, 1.75; 95% CI, 1.65-1.84), intensive care requirement (AOR, 1.48; 95% CI, 1.45-1.51) and perinatal death (AOR, 2.02; 95% CI, 1.78-2.29) were all higher in public hospitals. Conclusion: For women delivering a single baby at term in Australia, the prevalence of

Admission of Term Infants to Neonatal Intensive Care: A Population‐Based Study

Neonatal intensive care and special care nurseries provide a level of care that is both high in cost and low in volume. The aim of our study was to determine the rate of admission of term babies to neonatal intensive care in association with each method of giving birth among low-risk women. We examined the records of 1,001,249 women who gave birth in Australia during 1999 to 2002 using data from the National Perinatal Data Collection. Among low-risk women, we calculated the adjusted odds of admission to neonatal intensive care at term separated for each week of gestational age between 37 and 41 completed weeks. We also calculated the odds of admission to neonatal intensive care in association with cesarean section before or after the onset of labor, and vacuum or instrumental birth compared with unassisted vaginal birth at 40 weeks' gestation. The overall rate of admission to neonatal intensive care of term babies was 8.9 percent for primiparas and 6.3 percent for multiparas. After a cesarean section before the onset of labor, the adjusted odds of admission among low-risk primiparas at 37 weeks' gestation were 12.08 (99% CI 8.64-16.89); at 38 weeks, 7.49 (99% CI 5.54-10.11); and at 39 weeks, 2.80 (99% CI 2.02-3.88). At 41 weeks, the adjusted odds were not significantly higher than those at 40 weeks' gestation. Among low-risk multiparas who had a cesarean section before the onset of labor, the adjusted odds of admission to neonatal intensive care at 37 weeks' gestation were 15.40 (99% CI 12.87-18.43); at 38 weeks, 12.13 (99% CI 10.37-14.19); and at 39 weeks, 5.09 (99% CI 4.31-6.00). At 41 weeks' gestation, the adjusted odds of admission were significantly lower than those at 40 weeks (AOR 0.64, 99% CI 0.47-0.88). Babies born after any operative method of birth were at increased odds of being admitted to neonatal intensive care compared with those born after unassisted vaginal birth at 40 weeks' gestation. The adjusted odds of admission to neonatal intensive care for babies of low-risk women were increased after birth at 37 weeks' gestation. In a climate of rising cesarean sections, this information is important to women who may be considering elective procedures.

Birth Centers in Australia: A National Population‐Based Study of Perinatal Mortality Associated with Giving Birth in a Birth Center

Perinatal mortality is a rare outcome among babies born at term in developed countries after normal uncomplicated pregnancies; consequently, the numbers involved in large databases of routinely collected statistics provide a meaningful evaluation of these uncommon events. The National Perinatal Data Collection records the place of birth and information on the outcomes of pregnancy and childbirth for all women who give birth each year in Australia. Our objective was to describe the perinatal mortality associated with giving birth in "alongside hospital" birth centers in Australia during 1999 to 2002 using nationally collected data. This population-based study included all 1,001,249 women who gave birth in Australia during 1999 to 2002. Of these women, 21,800 (2.18%) gave birth in a birth center. Selected perinatal outcomes (including stillbirths and neonatal deaths) were described for the 4-year study period separately for first-time mothers and for women having a second or subsequent birth. A further comparison was made between deaths of low-risk term babies born in hospitals compared with deaths of term babies born in birth centers. The total perinatal death rate attributed to birth centers was significantly lower than that attributed to hospitals (1.51/1,000 vs 10.03/1,000). The perinatal mortality rate among term births to primiparas in birth centers compared with term births among low-risk primiparas in hospitals was 1.4 versus 1.9 per 1,000; the perinatal mortality rate among term births to multiparas in birth centers compared with term births among low-risk multiparas in hospitals was 0.6 versus 1.6 per 1,000. This study using Australian national data showed that the overall rate of perinatal mortality was lower in alongside hospital birth centers than in hospitals irrespective of the mother's parity.

The urban–remote divide for Indigenous perinatal outcomes

To determine whether remoteness category of residence of Indigenous women affects the perinatal outcomes of their newborn infants. A population-based study of 35 240 mothers identified as Indigenous and their 35 658 babies included in the National Perinatal Data Collection in 2001-2004. Australian Standard Geographical Classification remoteness category, birthweight, Apgar score at 5 minutes, stillbirth, gestational age and a constructed measure of perinatal outcomes of babies called "healthy baby" (live birth, singleton, 37-41 completed weeks' gestation, 2500-4499 g birthweight, and an Apgar score at 5 minutes >or= 7). The proportion of healthy babies in remote, regional and city areas was 74.9%, 77.7% and 77.6%, respectively. After adjusting for age, parity, smoking and diabetes or hypertension, babies born to mothers in remote areas were less likely to satisfy the study criteria of being a healthy baby (adjusted odds ratio [AOR], 0.87; 95% CI, 0.81-0.93) compared with those born in cities. Babies born to mothers living in remote areas had higher odds of being of low birthweight (AOR, 1.09; 95% CI, 1.01-1.19) and being born with an Apgar score < 7 at 5 minutes (AOR, 1.63; 95% CI, 1.39-1.92). Only three in four babies born to Indigenous mothers fell into the "healthy baby" category, and those born in more remote areas were particularly disadvantaged. These findings demonstrate the continuing need for urgent and concerted action to address the persistent perinatal inequity in the Indigenous population.

General obstetrics: Does size matter? A population‐based study of birth in lower volume maternity hospitals for low risk women

To study the association between volume of hospital births per annum and birth outcome for low risk women. Population-based study using the National Perinatal Data Collection (NPDC). Australia. Of 750,491 women who gave birth during 1999-2001, there were 331,147 (47.14%) medically 'low risk' including 132,696 (40.07%) primiparae and 198,451 (59.93%) multiparae. The frequency of each birth and infant outcome was described according to the size of the hospital where birth took place. We investigated whether unit size (defined by volume) was an independent risk factor for each outcome factor using public hospitals with greater than 2000 births per annum as a reference point. Rates of intervention at birth and neonatal mortality for low risk women in relation to hospitals with <100, 100-500, 501-1000, 1001-2000 and >2001 births per annum. Neonatal death was less likely in hospitals with less than 2000 births per annum regardless of parity. For multiparous low risk women in hospitals of 100 and 500 births per annum compared with hospitals of >2000 births per annum the adjusted odds of neonatal mortality [adjusted odds ratio (AOR) 0.36; 99% confidence interval (CI) 0.14-0.93]. For low risk primiparous women in hospitals with less than 100 births per annum, there were lower rates of induction of labour (AOR 0.62; 99% CI 0.54-0.73); intrathecal analgesia/anaesthesia (AOR 0.34; 99% CI 0.28-0.42); instrumental birth (AOR 0.80; 99% CI 0.69-0.93); caesarean section after labour (AOR 0.59; 99% CI 0.49-0.72) and admission to a neonatal unit (AOR 0.15; 99% CI 0.10-0.22) and for low risk multiparous women in hospitals with less than 100 births per annum: induction (AOR 0.69; 99% CI 0.62-0.76); intrathecal analgesia/anaesthesia (AOR 0.32; 99% CI 0.29-0.36); instrumental birth (AOR 0.52; 99% CI 0.41-0.67); caesarean section after labour (AOR 0.41; 99% CI 0.33-0.52); and admission to a neonatal unit (AOR 0.09; 99% CI 0.07-0.12). In Australia, lower hospital volume is not associated with adverse outcomes for low risk women.