Maternal factors and risk of spontaneous preterm birth due to high ambient temperatures in New South Wales, Australia.

BACKGROUND: Exposure to high ambient temperatures has been shown to increase the risk of spontaneous preterm birth. Determining which maternal factors increase or decrease this risk will inform climate adaptation strategies. OBJECTIVES: This study aims to assess the risk of spontaneous preterm birth associated with exposure to ambient temperature and differences in this relationship between mothers with different health and demographic characteristics. METHODS: We used quasi-Poisson distributed lag non-linear models to estimate the effect of high temperature-measured as the 95th percentile of daily minimum, mean and maximum compared with the median-on risk of spontaneous preterm birth (23-36 weeks of gestation) in pregnant women in New South Wales, Australia. We estimated the cumulative lagged effects of daily temperature and analyses on population subgroups to assess increased or decreased vulnerability to this effect. RESULTS: Pregnant women (n = 916,678) exposed at the 95th percentile of daily mean temperatures (25ºC) had an increased risk of preterm birth (relative risk 1.14, 95% confidence interval 1.07, 1.21) compared with the median daily mean temperature (17℃). Similar effect sizes were seen for the 95th percentile of minimum and maximum daily temperatures compared with the median. This risk was slightly higher among women with diabetes, hypertension, chronic illness and women who smoked during pregnancy. CONCLUSIONS: Higher temperatures increase the risk of preterm birth and women with pre-existing health conditions and who smoke during pregnancy are potentially more vulnerable to these effects.

Health care provider support and factors associated with breastfeeding beyond infancy: A cross-national study.

BACKGROUND: Breastfeeding beyond infancy (12 months) remains atypical in the United States, United Kingdom, Canada, and Australia, and the role of health care providers is unclear. The objective of this study was to compare women's perceptions of provider support and other factors affecting breastfeeding beyond infancy across countries, among women who had each successfully breastfed at least one child that long. METHODS: Women completed an online questionnaire distributed via La Leche League, USA (2013), about sources and ratings of support for breastfeeding for their oldest child who was breastfed at least 12 months and participant demographics. Multivariable log-binomial regression was used to compare ratings of health care provider support and the importance of 13 factors by country. RESULTS: Some similarities and many differences were observed across countries in support received from providers, whereas modest or no differences were observed in the importance women placed on factors like health benefits and enjoyment of breastfeeding. Of 59 581 women, less than half discussed their decision to breastfeed beyond infancy with their child's provider. United Kingdom women rated their comfort in discussing breastfeeding beyond 12 months with their providers and the support received as lower than United States women. Canadian women gave lower ratings than United States women, but inconsistently. Australian women rarely differed from United States women in their responses. Providers' recommendations were not important to the decision to breastfeed beyond infancy, especially for United Kingdom women. DISCUSSION: Rates of breastfeeding beyond infancy are low in these countries; improving provider support may help achieve global breastfeeding goals.

Rates of neonatal morbidity by maternal region of birth and gestational age in New South Wales, Australia 2003-2016.

INTRODUCTION: Research suggests that neonatal morbidity differs by maternal region of birth at different gestational ages. This study aimed to determine the overall and gestation-specific risk of neonatal morbidity by maternal region of birth, after adjustment for maternal, infant and birth characteristics, for women giving birth in New South Wales, Australia, from 2003 to 2016. MATERIAL AND METHODS: The study utilized a retrospective cohort study design using linked births, hospital and deaths data. Modified Poisson regression was used to determine risk with 95% confidence intervals (95% CI) of neonatal morbidity by maternal region of birth, overall and at each gestational age, compared with Australian or New Zealand-born women giving birth at 39 weeks. RESULTS: There were 1 074 930 live singleton births ≥32 weeks' gestation that met the study inclusion criteria, and 44 394 of these were classified as morbid, giving a neonatal morbidity rate of 4.13 per 100 live births. The gestational age-specific neonatal morbidity rate declined from 32 weeks' gestation, reaching a minimum at 39 weeks in all maternal regions of birth. The unadjusted neonatal morbidity rate was highest in South Asian-born women at most gestations. Adjusted rates of neonatal morbidity between 32 and 44 weeks were significantly lower for babies born to East (adjusted relative risk [aRR] 0.65, 95% CI 0.62-0.68), South-east (aRR 0.76, 95% CI 0.73-0.79) and West Asian-born (aRR 0.93, 95% CI 0.88-0.98) mothers, and higher for babies of Oceanian-born (aRR 1.11, 95% CI 1.04-1.18) mothers, compared with Australian or New Zealand-born mothers. Babies of African, Oceanian, South Asian and West Asian-born women had a lower adjusted risk of neonatal morbidity than Australian or New Zealand-born women until 37 or 38 weeks' gestation, and thereafter an equal or higher risk in the term and post-term periods. CONCLUSIONS: Maternal region of birth is an independent risk factor for neonatal morbidity in New South Wales.

Maternal exposure to fine particulate matter from a large coal mine fire is associated with gestational diabetes mellitus: A prospective cohort study.

BACKGROUND: In 2014, the Hazelwood coal mine fire was an unprecedented event that resulted in a six-week period of poor air quality in the Latrobe Valley in regional Australia. We aimed to determine whether maternal exposure to fine particulate matter in coal mine fire smoke was associated with selected obstetric complications, including gestational diabetes mellitus, hypertensive disorders of pregnancy and abnormal placentation. METHODS: We defined a complete cohort of pregnant women with births >20 weeks in the Latrobe Valley from March 1, 2012-Dec 31, 2015 utilising administrative perinatal data. Average and peak fine particulate matter (PM2.5) was assigned to residential address at delivery using a chemical transport model. Maternal, meteorological and temporal variables were included in final log-binomial regression models. RESULTS: 3612 singleton pregnancies were included in the analysis; 766 were exposed to the smoke event. Average maternal PM2.5 exposure was 4.4 µg/m3 (SD 7.7; IQR 2.12). Average peak PM2.5 exposure was 44.9 µg/m3 (SD 57.1; IQR 35.0). An interquartile range increase in peak PM2.5 was associated with a 16% increased likelihood of gestational diabetes mellitus (95%CI 1.09, 1.22; <0.0001). Whereas, an interquartile range increase in average PM2.5 was associated with a 7% increased likelihood of gestational diabetes mellitus (95%CI 1.03, 1.10; <0.0001). Second trimester exposure was of critical importance. No association for hypertensive disorders or abnormal placentation was observed. CONCLUSION: this is the first study to examine obstetric complications relating to a discrete smoke event. These findings may guide the public health response to future similar events.

Comparison of group O Rh(D)- red blood cell use in pregnant women across hospitals of various sizes and obstetric capabilities prior to the introduction of patient blood management guidelines.

BACKGROUND: O Rh(D)- red blood cell (RBC) units can generally be transfused to most patients regardless of their ABO blood type and are frequently used during emergency situations. Detailed usage patterns of O Rh(D)- RBC units in obstetric populations have not been well characterised. With the introduction of patient blood management guidelines, historical usage patterns are important for providing comparative data. AIMS: To determine how the use of O Rh(D)- RBC units in pregnant women differs between hospitals of different sizes and obstetric capabilities prior to patient blood management guidelines. METHODS: Data from 67 New South Wales public hospital blood banks were linked with hospital and perinatal databases to identify RBC transfusions during pregnancy, birth and postnatally between July 2006 and December 2010. RBC transfusions were divided into O Rh(D)- or other blood types. Hospitals were classified according to birth volume, obstetric capability and location, with transfusions classified by timing and diagnosis. RESULTS: Of the 12 078 RBC units transfused into pregnant women, 1062 (8.8%) were O Rh(D)-. Higher use of O Rh(D)- RBC units was seen in antenatal transfusions, preterm deliveries and in regional or smaller hospitals. There was wide variation in rates of O Rh(D)- RBC transfusion among hospitals. CONCLUSIONS: The rate of O Rh(D)- RBC unit use in obstetrics was lower during the period assessed than the nationally reported usage. It is encouraging that O Rh(D)- RBCs were more commonly used in emergency or specialised situations, or in facilities where holding a large blood inventory is not feasible.

Determining a strategy to reduce smoking in pregnancy.

BACKGROUND: Further efforts, informed by current data, are needed to reduce smoking during pregnancy. AIMS: To describe trends in smoking during pregnancy and identify regions most likely to benefit from targeted smoking cessation interventions, in New South Wales (NSW), Australia. MATERIALS AND METHODS: All women who gave birth in NSW between 1994 and 2016 were included. Smoking status was identified from the Perinatal Data Collection. For births between 2012 and 2016, women were grouped into Local Health District (LHD) of residence, and smoking rates calculated. The impacts of a hypothetical smoking cessation intervention in four LHDs with (i) high smoking rates and (ii) high numbers of smokers, were compared. RESULTS: The overall smoking rate during pregnancy decreased from 22.1% in 1994 to 8.3% in 2016. [Correction added on 13 August 2020, after first online publication: the overall smoking rate during pregnancy in 1994 has been corrected from 14.5% to 22.1%.]. The decrease was lowest among women living in the most socioeconomically disadvantaged areas (41%) and highest among those living in the most advantaged areas (83%). Between 2012 and 2016, over half the women who smoked during pregnancy lived in one of four LHDs. Only 1% of women reporting smoking during pregnancy resided in the LHD with the highest smoking rate (34.7%). A simulated intervention targeting only four regions showed greater effect on the statewide smoking rate when targeting LHDs with high numbers of smokers rather than high smoking rates. CONCLUSIONS: Despite decreases in rates of smoking during pregnancy, there was evidence of geographic clustering of smokers. The greatest reduction in overall smoking may come from interventions targeting the four LHDs with the highest number of smokers.

Gestational age, morbidity and mortality among twin births in New South Wales, Australia 2003-2014: A cohort study.

BACKGROUND: Evidence suggests that the trend toward early planned births observed among singletons may be evident among twin pregnancies. AIMS: To describe trends in gestational age at birth, pregnancy characteristics, neonatal morbidity and mortality among twin pregnancies. MATERIALS AND METHODS: Population-based data linkage study of twin births of ≥30 weeks of gestation without a major congenital anomaly born in 2003-2014 in New South Wales (NSW), Australia. Linked pregnancy and birth, hospital and mortality data were used. Generalised linear regression was used to assess linear trends. Risk difference (RD) and 95% confidence intervals were estimated. RESULTS: Among 28 076 eligible twin births (14 038 pregnancies), 49% of births occurred prior to 37 weeks and 69% of births were planned (pre-labour caesarean or induction of labour). There were increases over time in the proportion of twin births at preterm gestations (30-34 weeks (RD 2.1, 95% CI 0.1, 4.0), 35-36 weeks (RD 7.5, 95% CI 5.4, 9.7)) and in the rates of planned births (pre-labour caesarean (RD 6.4, 95% CI 4.0, 8.8), induction (RD 4.6, 95% CI 2.6, 6.6)). There was no significant change in stillbirth or neonatal death rates, but there was an increase in neonatal morbidity over the study period. Concurrently, there were increases in the prevalence of gestational diabetes; and decreases in pregnancy hypertension, assisted reproductive technology use, small-for-gestational age and birthweight discordance. CONCLUSIONS: Gestational age at birth among twin births is decreasing and birth intervention is increasing. There are increasing rates of neonatal morbidity, but no overall change in perinatal mortality.

Rates of stillbirth by maternal region of birth and gestational age in New South Wales, Australia 2004-2015.

BACKGROUND: Research suggests that in Australia, maternal region of birth is a risk factor for stillbirth. AIMS: We aimed to examine the relationship between stillbirth and maternal region of birth in New South Wales (NSW), Australia from 2004 to 2015. METHODS: Adjusted logistic regression was used to determine odds of stillbirth by maternal region of birth, compared with Australian or New Zealand-born (AUS/NZ-born) women. Intervention rates (induction or pre-labour caesarean) by maternal region of birth, over time, were also examined. Interaction terms were used to assess change in relative odds of stillbirth, over two time periods (2004-2011 and 2012-2015). RESULTS: There were 944 457 singleton births ≥24 weeks gestation that met the study inclusion criteria and 3221 of these were stillbirths, giving a stillbirth rate of 3.4 per 1000 births. After adjustment for confounders, South Asian (adjusted odds ratio (aOR) 1.42, 95% CI 1.24-1.62), Oceanian (aOR 1.45, 95% CI 1.17-1.80) and African (aOR 1.46, 96% CI 1.19-1.80) born women had significantly higher odds of stillbirth that AUS/NZ-born women. Intervention rates increased from the earlier to the later time period by 13.1% across the study population, but the increase was larger in African and South Asian-born women (18.1% and 19.6% respectively) than AUS/NZ-born women (11.2%). There was a significant interaction between ethnicity and time period for South Asian-born women in the all-births model, with their stillbirth rates becoming closer to AUS/NZ-born women in the later period. CONCLUSION: South Asian, African and Oceanian maternal region of birth are independent risk factors for stillbirth in NSW.

Haemoglobin trajectories during pregnancy and associated outcomes using pooled maternity and hospitalization data from two tertiary hospitals.

BACKGROUND AND OBJECTIVES: This study aimed to describe how haemoglobin trajectories in pregnant Australian women were associated with subsequent postpartum haemorrhage, blood transfusion and other outcomes. MATERIALS AND METHODS: The study was conducted in two tertiary public hospitals in Australia, using routinely collected maternity and hospital data on singleton pregnancies (2011-2015). Latent class growth modelling defined trajectories among those with at least one haemoglobin in each of three antenatal time periods (0-15, 16-30 and 31+ weeks; n = 7104). Observed over expected ratios were calculated after predicting expected outcomes with adjusted logistic regression. RESULTS: The mean minimum haemoglobin levels across the three periods were 127·9, 116·5 and 119·3 g/l. We identified seven groups of women with similar haemoglobin trajectories: five with parallel U-shaped trajectories, one with increasing and one with decreasing trajectory. Thirty-eight women (0.5%) had very low haemoglobin across the pregnancy and the highest adverse outcomes, including higher than expected blood transfusion risk. One hundred thirteen women (1.6%) with a progressively decreasing trajectory also had higher risk of transfusion. Women with high haemoglobin across the antenatal period had higher than expected risk of preterm birth, small for gestational age and infants transferred to higher care. CONCLUSIONS: Haemoglobin trajectories across pregnancy can predict women at higher risk of requiring transfusion around birth. Women who maintain high haemoglobins across the pregnancy are worthy of increased surveillance as they carry increased risks of newborn morbidity.

Childhood health and education outcomes following early term induction for large-for-gestational age: A population-based record linkage study.

INTRODUCTION: There is debate about optimal management of pregnancies with a large-for-gestational age baby. A recent randomized controlled trial reported that early term induction of labor reduced cesarean section rates and infant morbidity. However, long term childhood outcomes have not been assessed. The aim of this study was to assess maternal, neonatal and child health and education outcomes for large-for-gestational age babies induced at 37-38 weeks' gestation. MATERIAL AND METHODS: Population-based record linkage study of term (37+ weeks), cephalic-presenting singleton pregnancies with a large-for-gestational age baby in New South Wales, Australia, 2002-2006. Linked birth, hospital, mortality and education data were used with at least 9 years follow up from birth. Exposure was induction of labor at 37-38 weeks, compared to expectant management (spontaneous birth at ≥37 weeks and planned births at ≥39 weeks). Relative risks and 95% confidence intervals were estimated using Modified Poisson regression with robust variance. RESULTS: Among 10 174 eligible pregnancies, 412 (4.0%) had an induction at 37-38 weeks. Women in the induction group were less likely to have a cesarean section (RR: 0.65, 95% CI: 0.51-0.82). Infants had higher rates of: low Apgar scores, birth trauma, neonatal jaundice and phototherapy use, and admission to special care nursery or neonatal intensive care than their expectantly managed counterparts. As children, they had higher rates of hospital admission (RR: 1.16, 95% CI: 1.04-1.30) and special needs (RR: 1.98, 95% CI: 1.12-3.50). However, by age 8 there was no difference in overall literacy and numeracy achievement. CONCLUSIONS: Although women who had an early term labor induction with large-for-gestational age were less likely to have a cesarean section, the increased risk of neonatal morbidities and additional healthcare utilization suggests the need for caution in early induction of large-for-gestational age babies before 39 weeks' gestation.

Mortality and hospital readmissions in the first year of life after intra-uterine and neonatal blood product transfusions: A population data linkage study.

AIM: Blood product transfusions are a potentially life-saving therapy for fetal and neonatal anaemia, but there is limited population-based research on outcomes. We aimed to describe mortality, readmission and average hospital stay in the first year of life for infants with or without intra-uterine or neonatal blood product transfusions. METHODS: Linked birth, hospital and deaths data from New South Wales, Australia (January 2002-June 2014) were used to identify singleton infants (≥23 weeks' gestation, surviving to 29 days; n = 1 089 750) with intra-uterine or neonatal transfusion or no transfusion. Rates of mortality and readmission in the first year (29-365 days) and days in hospital were calculated. RESULTS: Overall, 68 (0.06/1000) infants had experienced intra-uterine transfusion and 4332 (3.98/1000) neonatal transfusion. Transfusion was more common among those born at earlier gestational ages requiring invasive ventilation. Mortality, readmissions and average days in hospital were higher among transfused than non-transfused infants. Over half of infants with intra-uterine and neonatal transfusion had ≥1 readmission in the first 29-365 days (55.9 and 51.8%, respectively), and around a quarter had ≥2 (20.6 and 28.5%, respectively) compared with 15.3% with ≥1 and 3.5% with ≥2 in the non-transfused group. CONCLUSION: Infants with a history of blood product transfusion, particularly those needing a neonatal transfusion, had higher mortality and more frequent contact with the hospital system in the first year of life than those infants with no history of transfusion.

Appendicectomy during pregnancy and the risk of preterm birth: A population data linkage study.

BACKGROUND: Suspected appendicitis is a common non-obstetric indication for emergency abdominal surgery during pregnancy. AIMS: Assess the risk of preterm birth and other maternal and neonatal adverse birth outcomes following appendicectomy during pregnancy. MATERIALS AND METHODS: Population-based data linkage study of women with singleton births in New South Wales, Australia, 2002-2014. Pregnancies with appendicitis and appendicectomy were compared to pregnancies without appendicitis. Crude and adjusted hazard ratios (aHR) with 95% confidence intervals (CI) for preterm birth were estimated. Modified Poisson regression with robust variance was used to estimate crude and adjusted risk ratios (aRR) with 99% CI for other outcomes. RESULTS: Of 1 124 551 eligible pregnancies, 1024 (0.9/1000 pregnancies) had appendicitis and appendicectomy. Of these, 566 (55.3%) had laparoscopic and 458 (44.7%) had open appendicectomy. Appendicectomy at later gestational ages was associated with increasing rates of preterm birth. After adjustment for maternal and pregnancy factors, appendicectomy was associated with increased risk of preterm birth (overall aHR 1.73, 95% CI 1.42-2.09; planned aHR 2.08, 95% CI 1.60-2.72), maternal morbidity (aRR 2.68, 99% CI 1.88-3.83) and neonatal morbidity (aRR 1.42, 99% CI 1.03-1.94). However, there was no difference in perinatal mortality rates. CONCLUSION: Appendicectomy during pregnancy is associated with increased risk of spontaneous and planned preterm birth, maternal and neonatal morbidity. Availability of resources to prevent or manage preterm labour should be considered when appendicectomy is performed at gestational ages of 20 weeks or more.

Outcomes associated with transfusion in low-risk women with obstetric haemorrhage.

BACKGROUND AND OBJECTIVES: Obstetric haemorrhage is associated with increased blood transfusion, morbidity and health service usage in women. While the use of transfusion in actively bleeding patients is supported, there is little evidence for the use of blood as treatment in the nonbleeding patient following obstetric haemorrhage. Transfusion may expose women to increased morbidity. This study aims to compare outcomes between low-risk women receiving no or 1-2 units of blood in the context of obstetric haemorrhage. MATERIALS AND METHODS: The study population included women giving birth in hospital in New South Wales, Australia, between July 2006 and December 2010, with a diagnosis of obstetric haemorrhage. Women with medical or obstetric conditions making them high risk were excluded, as were women receiving more than 2 units of blood. Data were obtained from linked hospital, birth and blood bank databases. Propensity score matching was used to compare outcomes between transfused and nontransfused women in order to estimate the impact of the transfusion itself on outcomes. RESULTS: There were 14989 women with obstetric haemorrhage, of whom, 1702 received a transfusion, including 1069 receiving a transfusion of 1-2 units. Women receiving transfusion were more likely to experience severe maternal morbidity (relative risk 7·0, 95% Confidence interval (2·8, 17·8)), be admitted to intensive care (RR 2·1 95% CI(1·2, 3·8)), and have a length of stay >5 days (RR 2·0, 95% CI (1·6, 2·5)). CONCLUSIONS: Small volume transfusion in the context of obstetric haemorrhage among low-risk women is associated with poorer maternal outcomes and increased healthcare utilisation.

Assessing the effect of risk factors on rates of obstetric transfusion over time using two methodological approaches.

BACKGROUND: While red blood cell transfusion rates have declined in most Australian medical specialties, obstetric transfusion rates have instead been increasing. Obstetric transfusions are mostly linked to postpartum haemorrhage, the rates of which have also increased over time. This study used two methodological approaches to investigate recent trends in obstetric transfusion in New South Wales (NSW) and the extent to which this was influenced by changing maternal and pregnancy characteristics. METHODS: Linked birth and hospital records were used to examine rates of red blood cell transfusion in the postpartum period for mothers giving birth in NSW hospitals from 2005 to 2015. Logistic regression models were run to examine the contribution of maternal and pregnancy risk factors to changing rates of transfusion. Risk factors were divided into "pre-pregnancy" and "pregnancy related". Crude and adjusted estimates of the effect of year of birth on obstetric transfusion rates were compared to assess the effect of risk factors on rates over time using two approaches. The first compared actual and predicted odds ratios of transfusion for each year. The second compared the observed increase in transfusion rate with that predicted after controlling for the risk factors. RESULTS: Among 935,659 births, the rate of obstetric transfusion rose from 13 per 1000 births in 2005 to 17 in 2011, and remained stable until 2015. From 2005 to 2015, postpartum haemorrhage increased from 74 to 114 per 1000 births. Compared with the rate in 2005, the available maternal and pregnancy characteristics only partially explained the change in rate of transfusion by 2015 (Method 1, crude odds ratio 1.39 (95% CI 1.25, 1.56); adjusted odds ratio 1.29 (95% CI 1.15, 1.45)). After adjustment for maternal and pregnancy characteristics, obstetric transfusion incidence was predicted to increase by 10.3%, but a 38.7% increase was observed (Method 2). CONCLUSION: Rates of obstetric transfusion have stabilised after a period of increase. The trend could not be fully explained by measured maternal and pregnancy characteristics with either of the two approaches. Further investigation of rates and maternal and clinical risk factors will help to inform and improve obstetric blood product use.

Comparison of neonatal red cell transfusion reporting in neonatal intensive care units with blood product issue data: a validation study.

BACKGROUND: Infants in Neonatal Intensive Care Units represent a heavily transfused population, and are the focus of much research interest. Such research commonly relies on custom research databases or routinely collected data. Knowledge of the accuracy of transfusion recording in these databases is important. This study aims to assess the reporting of red blood cell transfusion neonatal intensive care unit data compared with routinely collected hospital blood bank ("Blood Watch") data. METHODS: Blood Watch data was linked with the NICUS Data Collection, and with routinely collected birth and hospital data for births between 2007 and 2010. The sensitivity, specificity, and positive and negative predictive values for transfusion were calculated, compared to the Blood Watch data. The agreement between the NICUS and Blood Watch datasets on quantity transfused was also assessed. RESULTS: Data was available on 3934 infants, of which 16.2% were transfused. Transfusion was reported in the NICUS Data Collection with high specificity (98.3%, 95% confidence interval (97.8%,98.7%)), but with some under-enumeration (sensitivity 89.2% (95% CI 86.5%,91.5%)). There was excellent agreement between the NICUS and Blood Watch datasets on quantity transfused (Kappa 0.90, 95% CI (0.88,0.92)). Transfusion reporting in the hospital data for these infants was also reliably reported (Sensitivity 83.7% (95% CI 80.6%,86.5%), specificity 99.1% (95% CI 98.7%,99.4%)). CONCLUSIONS: Transfusion is reliably reported in the neonatal intensive care unit data, with some under-reporting, and quantity transfused is well recorded. The NICUS Data Collection provides useful information on blood transfusions, including quantity of blood transfused in a high risk population.

Contribution of maternal age, medical and obstetric history to maternal and perinatal morbidity/mortality for women aged 35 or older.

BACKGROUND: As age is not modifiable, pregnancy risk information based on age alone is unhelpful for older women. AIM: To determine severe morbidity/mortality rates for women aged ≥35 years according to maternal profile based on parity, pre-existing medical conditions and prior pregnancy complications, and to assess the independent contribution of age. MATERIALS AND METHODS: Population-based record-linkage study using NSW hospitalisation and birth records 2006-2012. Maternal and perinatal mortality/morbidity were assessed for non-anomalous singleton births to women aged ≥35 years. RESULTS: For 117 357 pregnancies among 99 375 women aged ≥35 years, the median age at delivery was 37 years (range 35-56 years), including: 35 652 (30.4%) multiparae without pre-existing medical or obstetric complications, 33,058 (28.2%) nulliparae without pre-existing medical conditions and 30 325 (25.8%) multiparae with prior pregnancy complications. Maternal and perinatal mortality/morbidity varied by maternal profile with ranges of 0.9-3.5% and 2.4-11.9%, respectively. For nulliparae, each five-year increase in age did not contribute significantly to maternal risk after controlling for medical conditions (adjustedodds ratio 1.08, 95% CI 0.93-1.25), but did confer perinatal risk (1.14; 1.05-1.25). For multiparae, each five-year increase in age beyond 35 years was independently associated with adverse maternal (1.23; 1.09-1.39) and perinatal outcomes (1.23; 1.09-1.39). CONCLUSIONS: For women aged ≥35 years, presence of medical conditions conferred a greater risk for morbidity/mortality than age itself. For multiparous women, the effects of medical and obstetric history were additive. The contribution of maternal age to adverse outcomes in pregnancies without significant medical and obstetric history is modest.

Outcomes of Gallstone Disease during Pregnancy: a Population-based Data Linkage Study.

BACKGROUND: Gallstone disease is a leading indication for non-obstetric abdominal surgery during pregnancy. There are limited whole population data on maternal and neonatal outcomes. This population-based study aims to describe the outcomes of gallstone disease during pregnancy in an Australian setting. METHODS: Linked hospital, birth, and mortality data for all women with singleton pregnancies in New South Wales, Australia, 2001-2012 were analysed. Exposure of interest was gallstone disease (acute biliary pancreatitis, gallstones with/without cholecystitis). Outcomes including preterm birth (spontaneous and planned), readmission, morbidity and mortality (maternal and neonatal) were compared between pregnancies with and without gallstone disease. Adjusted risk ratios (aRRs) and 99% confidence intervals were estimated using modified Poisson regression and adjusted for maternal and pregnancy factors. RESULTS: Among 1 064 089 pregnancies, 1882 (0.18%) had gallstone disease. Of these, 239 (12.7%) had an antepartum cholecystectomy and 1643 (87.3%) were managed conservatively. Of those managed conservatively, 319 (19.0%) had a postpartum cholecystectomy. Gallstone disease was associated with increased risk of preterm birth (aRR 1.3, 99% CI 1.1, 1.6), particularly planned preterm birth (aRR 1.6, 99% CI 1.2, 2.1), maternal morbidity (aRR 1.6, 99% CI 1.1, 2.3), maternal readmission (aRR 4.7, 99% CI 4.2, 5.3), and neonatal morbidity (aRR 1.4, 99% CI 1.1, 1.7). Surgery was associated with decreased risk of maternal readmission (aRR 0.4, 99% CI 0.2, 0.7). CONCLUSIONS: Gallstone disease during pregnancy was associated with adverse maternal and neonatal outcomes. Most women with gallstone disease during pregnancy are managed conservatively. Surgical management was associated with decreased risk of readmission.

Uptake of external cephalic version for term breech presentation: an Australian population study, 2002-2012.

BACKGROUND: The safety, efficacy, and cost-effectiveness of external cephalic version (ECV) for term breech presentation has been demonstrated. Clinical guidelines recommend ECV for all eligible women, but the uptake of this procedure in the Australian healthcare setting is unknown. This study aimed to describe ECV uptake in New South Wales, the most populous state of Australia, during 2002 to 2012. METHODS: Data from routine hospital and birth records were used to identify ECVs conducted at ≥36 weeks' gestation. Women with ECV were compared to women who were potentially eligible for but did not have ECV. Eligibility for ECV was based on clinical guidelines. For those with ECV, birth outcomes following successful and unsuccessful procedures were examined. RESULTS: In N = 32,321 singleton breech pregnancies, 10.5% had ECV, 22.3% were ineligible, and 67.2% were potentially eligible but did not undergo ECV. Compared to women who were eligible but who did not attempt ECV, those who had ECV were more likely to be older, multiparous, overseas-born, public patients at delivery, and to deliver in tertiary hospitals in urban areas (p < 0.01). Fewer women who underwent ECV smoked during pregnancy, fewer were morbidly obese, and fewer had a hypertensive disorder of pregnancy, compared to those who were eligible. Caesarean section occurred in 25.9% of successful compared to 95.6% of unsuccessful ECVs. Infant outcomes did not differ by ECV success. CONCLUSIONS: The majority of women with a breech presentation did not receive ECV. It is unclear whether this is attributable to issues with service provision or low acceptability among women. Policies to improve access to and information about ECV appear necessary to improve uptake among women with term breech presentation. Improved data collection around the diagnosis of breech presentation, ECV attempts, and outcomes may help to identify specific barriers to ECV uptake.

Long-term childhood outcomes of breech presentation by intended mode of delivery: a population record linkage study.

INTRODUCTION: There is a lack of information on long-term outcomes by mode of delivery for term breech presentation. We aimed to compare childhood mortality, cerebral palsy, hospitalizations, developmental, and educational outcomes associated with intended vaginal breech birth (VBB) with planned cesarean section. MATERIAL AND METHODS: Population birth and hospital records from New South Wales, Australia, were used to identify women with non-anomalous pregnancies eligible for VBB during 2001-2012. Intended mode of delivery was inferred from labor onset and management. Death, hospital, and education records were used for follow up until 2014. Cox proportional hazards regression and modified Poisson regression were used for analysis. RESULTS: Of 15 281 women considered eligible for VBB, 7.7% intended VBB, 74.2% planned cesarean section, and intention was uncertain for 18.1%. Intended VBB did not differ from planned cesarean section on infant mortality (Fisher's exact p = 0.55), childhood mortality (Fisher's exact p = 0.50), cerebral palsy (Fisher's exact p = 1.00), hospitalization in the first year of life [adjusted hazard ratio (HR) 1.04; 95% CI 0.90-1.20], hospitalization between the first and sixth birthdays (HR 0.92; 95% CI 0.82-1.04), being developmentally vulnerable [adjusted relative risk (RR) 1.22; 95% CI 0.48-1.69] or having special needs status (RR 0.95; 95% CI 0.48-1.88) when aged 4-6, or scoring more than 1 standard deviation below the mean on tests of reading (RR 1.10; 95% CI 0.87-1.40) and numeracy (RR 1.04; 95% CI 0.81-1.34) when aged 7-9. CONCLUSIONS: Planned VBB confers no additional risks for child health, development or educational achievement compared with planned cesarean section.

Maternal and neonatal outcomes following abnormally invasive placenta: a population-based record linkage study.

INTRODUCTION: Abnormally invasive placenta involves abnormal adherence of the placenta to the myometrium and is associated with severe pregnancy complications such as blood transfusion and hysterectomy. Knowledge of outcomes has been limited by small sample sizes and a focus on maternal rather than neonatal outcomes. This study uses population-level data collected over 10 years to investigate maternal and neonatal outcomes and trends in incidence of abnormally invasive placenta (also known as placenta accreta, increta and percreta). MATERIAL AND METHODS: A population-based record linkage study was performed, including all women who gave birth in New South Wales, Australia, between 2003 and 2012. Data were obtained from birth records, hospital admissions and deaths registrations. Modified Poisson regression models, adjusted for confounding factors, were used to quantify the effect of abnormally invasive placenta on adverse maternal and neonatal outcomes. RESULTS: Abnormally invasive placenta was significantly associated with morbidity for mothers (adjusted relative risk 17.6, 99% confidence interval 14.5-21.2) and infants (adjusted relative risk 3.1, 99% confidence interval 2.7-3.5). Abnormally invasive placenta increased risk of stillbirth (relative risk 5.4, 99% confidence interval 4.0-7.3) and neonatal death (relative risk 8.0, 99% confidence interval 1.5-41.6). The overall rate of abnormally invasive placenta was 24.8 per 10 000 deliveries, and 22.7 per 10 000 among primiparae. Incidence increased by 30%, from 20.6 to 26.9 per 10 000, over the 10-year study period. CONCLUSIONS: Abnormally invasive placenta substantially increases the risk of severe adverse outcomes for mothers and babies, and the incidence is increasing. Delivery should occur in tertiary hospitals equipped with neonatal intensive care units. Clinicians should be cognizant of the risks, particularly to infants, and maintain a high index of suspicion of abnormally invasive placenta, including in primiparae.