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Objectives: To describe the population of women having bariatric surgery and compare the pregnancy outcomes for women having bariatric surgery with a non-bariatric surgery population having a first and second pregnancy.Design: Population-based record linkage study.Setting: New South Wales (NSW), Australia.Population: All women aged 15-45 years with a hospital record in NSW (2002-2014) and all women giving birth in NSW (1994-2015; n = 1 606 737 women).Methods: Pregnancy and birth outcomes were compared between first and second pregnancies using repeated-measures logistic regression and paired Student's t-tests. Bariatric and non-bariatric groups were also compared.Main Outcome Measures: Maternal diabetes, preterm birth (<37 weeks of gestation) and large for gestational age.Results: There was a 13-fold increase in hospitalisations for primary bariatric surgery during 2002-2014. Compared with the general birthing population, women who had bariatric surgery experienced higher rates of hypertension, diabetes, and preterm birth. Among women who had bariatric surgery between a first and second pregnancy, there were reduced rates of hypertension (OR 0.39, 95% CI 0.29-0.53), spontaneous preterm birth (OR 0.37, 95% CI 0.16-0.86), infants that were large for gestational age (OR 0.63, 95% CI 0.44-0.88), and the admission of infants to a special care nursery or neonatal intensive care (OR 0.64, 95% CI 0.46-0.90) in the second pregnancy. Rates for small-for-gestational age and gestational diabetes following surgery were 8.3 and 11.4%, respectively CONCLUSIONS: Bariatric surgery between a first and second pregnancy was associated with reductions in obesity-related adverse pregnancy outcomes. Bariatric surgery performed for the management of obesity in accordance with current clinical criteria is associated with improved pregnancy outcomes in a subsequent pregnancy.Tweetable Abstract: Bariatric surgery for obesity may improve pregnancy and birth outcomes in a subsequent pregnancy. [ABSTRACT FROM AUTHOR]

Background and Objectives To explore variation in red blood cell transfusion rates between hospitals, and the extent to which this can be explained. A secondary objective was to assess whether hospital transfusion rates are associated with maternal morbidity. Materials and Methods Linked hospital discharge and birth data were used to identify births ( n = 279 145) in hospitals with at least 10 deliveries per annum between 2008 and 2010 in New South Wales, Australia. To investigate transfusion rates, a series of random-effects multilevel logistic regression models were fitted, progressively adjusting for maternal, obstetric and hospital factors. Correlations between hospital transfusion and maternal, neonatal morbidity and readmission rates were assessed. Results Overall, the transfusion rate was 1·4% (hospital range 0·6-2·9) across 89 hospitals. Adjusting for maternal casemix reduced the variation between hospitals by 26%. Adjustment for obstetric interventions further reduced variation by 8% and a further 39% after adjustment for hospital type (range 1·1-2·0%). At a hospital level, high transfusion rates were moderately correlated with maternal morbidity (0·59, P = 0·01), but not with low Apgar scores (0·39, P = 0·08), or readmission rates (0·18, P = 0·29). Conclusion Both casemix and practice differences contributed to the variation in transfusion rates between hospitals. The relationship between outcomes and transfusion rates was variable; however, low transfusion rates were not associated with worse outcomes. [ABSTRACT FROM AUTHOR]

Background: Increasing rates of induction have been reported in the UK, the USA, Canada and Australia since the early 1990s; however, there is a lack of population-based studies on trends and pharmacological management of induction of labour. Aims: To determine population trends in induction of labour and predictors of failed induction (in caesarean section, specifically for failure to progress with cervix dilation ≤3 cm). Methods: Trends in induction were determined for women in NSW who laboured at ≥ 32 weeks from 1998 to 2007 ( N = 739 904). To determine the predictors of failed induction, 92 359 deliveries of live singletons for whom linked birth and hospital data were available (2001–2005) were examined using logistic regression analysis. Results: The rate of induction increased over the decade from 25.3 to 29.1%; however, among those induced with prostaglandin alone, it decreased from 33.5 to 23.8%. Oxytocin alone was the most commonly used labour induction agent overall (51%) and in most population subgroups. The predictors of failed induction in both nullipara and multipara included increasing maternal age, pre-term and post-term birth and the use of prostaglandin or mechanical methods of induction (neither oxytocin nor prostaglandin). Conclusions: The pharmacological agents used for induction of labour have changed over the past decade. An important area for future research is to investigate how the dosage of oxytocin and prostaglandin affects pregnancy outcomes. [ABSTRACT FROM AUTHOR]

Background: Little is known about the pregnancy outcomes of women who have had a stroke prior to a first pregnancy., Aim: To identify a cohort of primiparous women giving birth to a single baby and compare the pregnancy outcomes of those with a pre-pregnancy stroke hospitalisation record to those without a stroke hospitalisation record., Materials and Methods: Record linkage study of all primiparous women aged 15-44 years with singleton pregnancies birthing in New South Wales, Australia from 2003 to 2015. Stroke was identified from 2001 to 2015 hospital data using International Classification of Diseases tenth Edition - Australian Modification codes I60-64. Women whose first hospital record of stroke was during pregnancy or <42 days after birth were excluded. Outcomes included diabetes or hypertension during pregnancy, mode of delivery, haemorrhage, severe maternal morbidity (validated composite outcome indicator), gestational age at birth, Apgar score (1 min < 7), and small-for-gestational age., Results: Of 487 767 women with a first pregnancy, 124 (2.5/10 000) had a hospital record which included a pre-pregnancy stroke diagnosis. Women with a stroke history were more likely to have an early-term delivery (37-38 weeks; relative risk (RR) 1.49, 95% CI 1.17-1.90) and a pre-labour caesarean (RR 2.83, 95% CI 2.20-3.63). There were no significant differences in other maternal or neonatal outcomes., Conclusion: This is the largest reported study of pregnancy and birth outcomes for women with a history of stroke. With the exception of pre-labour caesarean, there were no differences in pregnancy outcomes for women with a history of stroke compared with women with no history of stroke., (© 2020 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.)

Introduction: There is a lack of evidence around the risk of transfusion following vaginal birth after cesarean (VBAC) compared with elective repeat cesarean section (ERCS); this is important for decision-making about birth options. The aim of this study was to determine transfusion rates and risk of transfusion following intended VBAC and ERCS., Material and Methods: Women with a primary cesarean who had a subsequent birth at term (≥37 weeks) in New South Wales between 2000 and 2012, were identified from the New South Wales Perinatal Data Collection. Blood transfusions were identified from linked hospital records. Women deemed ineligible for VBAC were excluded. Modified Poisson regression was used to determine transfusion risk associated with intended VBAC compared with ERCS. Intended mode of birth was classified as: (1) intended VBAC and vaginal birth, (2) intended VBAC and cesarean, (3) intended ERCS and (4) "intention uncertain"., Results: A total of 90 439 women were eligible for VBAC. Rates of transfusion were: 1.4% for intended VBAC and vaginal birth (n = 17 849); 1.2% for intended VBAC and cesarean (n = 7648); 0.3% for intended ERCS (n = 60 471); and 1.1% for "intention uncertain" (n = 4471). After adjusting for maternal and pregnancy characteristics, risk of transfusion was almost four times higher for women classified as intended VBAC than intended ERCS (adjusted risk ratio = 3.73, 95% confidence interval 2.90-4.78)., Conclusions: Following a prior primary cesarean, there was a higher risk of transfusion associated with attempting VBAC compared with ERCS. Though the absolute risk is small, it is important for women considering VBAC to choose birthing facilities with ready access to blood products., (© 2018 Nordic Federation of Societies of Obstetrics and Gynecology.)

Objective: The aim of this study was to determine the association between red blood cell transfusion and breastfeeding among women who have suffered a postpartum haemorrhage at birth taking into account post-birth haemoglobin concentrations., Results: Among 15,451 maternities with postpartum haemorrhage in New South Wales public hospitals between 2007 and 2010, 1828 (12%) received a red cell transfusion. Among transfused women, 686 (38%) had haemoglobin concentration pre-transfusion < 70 g/L, 792 (43%) had 70-90 g/L, and 350 (19%) had > 90 g/L. Rates and adjusted relative risks (aRR) for breastfeeding at hospital discharge were as follows: for women with haemoglobin concentrations < 70 g/L following birth and received a transfusion, 78.6% were breastfeeding and the aRR of breastfeeding compared to untransfused women was 0.90 (99% confidence interval (CI) 0.86-0.95); for women with haemoglobin concentrations 70-90 g/L, 81.3% were breastfeeding, aRR 0.94 (99% CI 0.90-0.98); and for women with haemoglobin concentrations > 90 g/L, 80.9% were breastfeeding, aRR 0.94 (99% CI 0.88-1.00).

Objective: To explore the variation in hospital caesarean section (CS) rates for nulliparous women, to determine whether different case-mix, labour and delivery, and hospital factors can explain this variation and to examine the association between hospital CS rates and outcomes., Design: Population-based cohort study., Setting: New South Wales, 2009-2010., Population: Nulliparous women with singleton cephalic live births at term., Methods: Random effect multilevel logistic regression models using linked hospital discharge and birth data., Main Outcome Measures: Prelabour and intrapartum CS rates following spontaneous labour or labour induction; maternal and neonatal severe morbidity rates., Results: Of 67 239 nulliparous women, 4902 (7.3%) had a prelabour CS, 39 049 (58.1%) laboured spontaneously, and 23 288 (34.6%) had labour induced. Overall, there were 18 875 (28.1%) CSs, with labour inductions twice as likely to result in an intrapartum CS compared with women with a spontaneous onset of labour (34.0% versus 15.5%). After adjusting for differences in case-mix, labour and delivery, and hospital factors, the overall variation in CS rates decreased by 78% for prelabour CSs, 52% for intrapartum CSs following spontaneous labour and 9% following labour induction. Adjusting for labour and delivery practices increased the unexplained variation in intrapartum CSs. The adjusted rates of severe maternal and neonatal morbidity were not significantly different across CS rate quintile groups, except for women in spontaneous labour, where the hospitals in the lowest CS quintile had the lowest neonatal morbidity rate., Conclusions: Differences in clinical practice were substantial contributors to variation in intrapartum CS rates. Our findings suggest that CS rates in some hospitals could be lowered without adversely affect pregnancy outcomes., (© 2015 Royal College of Obstetricians and Gynaecologists.)

Aims: To determine occurrence and recurrence rates of gestational diabetes among women having at least two consecutive pregnancies. Risk factors for recurrence of gestational diabetes and rates of second/third pregnancy pre-existing diabetes mellitus were also assessed., Methods: Population-based study using longitudinally linked hospital discharge and birth records (2001-2009) in NSW, Australia. Participants included women without a pre-existing diagnosis of Type 1 or Type 2 diabetes at time of first pregnancy and with at least a first and second birth. Factors associated with recurrence of gestational diabetes were examined using multivariate log-binomial models to adjust for correlation within mothers and estimate relative risks and 95% confidence intervals., Results: First occurrence of gestational diabetes was 3.7% (5315/142 843) in the first pregnancy and 2.7% (3689/137 528) in the second pregnancy. The recurrence rate of gestational diabetes in a second consecutive pregnancy was 41.2%. Risk of pre-existing diabetes in a pregnancy subsequent to one with first occurrence of gestational diabetes was 2.2% and 2.0% in the second or third pregnancy, respectively. Among women with a diagnosis of gestational diabetes in the first pregnancy, independent predictors of gestational diabetes recurrence were maternal age ≥ 35 years, ethnicity (Middle East/North Africa and Asia), pregnancy hypertension, large for gestational age infant and preterm birth in the first pregnancy, longer inter-pregnancy birth interval and pregnancy hypertension and multiple pregnancy in the second pregnancy., Conclusions: Gestational diabetes in a previous pregnancy is a strong indicator of future risk and a useful clinical marker for identifying women at elevated risk in a subsequent pregnancy., (© 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.)

Objective: To investigate the recurrence risk of breech presentation at term, and to assess the risk factors that contribute to its recurrence., Design: Cohort study., Setting: New South Wales, Australia., Population: Women with their first two (n = 113 854) and first three (n = 21 690) consecutive singleton term pregnancies, in the period 1994-2002., Methods: Descriptive statistics including rates, relative risks and adjusted relative risks, as determined from logistic regression and Poisson analyses., Main Outcome Measures: Rates and risks of occurrence and recurrence of breech presentation at birth in each pregnancy, and maternal and infant risk factors associated with breech recurrence., Results: First-time breech presentation at term occurred in 4.2% of first pregnancy deliveries, 2.2% of second pregnancies and 1.9% of third pregnancies. The rate of breech recurrence in a second consecutive pregnancy was 9.9%, and in a third consecutive pregnancy (after two prior breech deliveries) was 27.5%. The relative risk of breech recurrence in a second pregnancy was 3.2 (95% CI 2.8-3.6), and in a third consecutive breech pregnancy was 13.9 (95% CI 8.8-22.1). First pregnancy factors associated with recurrence included placenta praevia [adjusted relative risk (aRR) 2.2; 95% CI 1.3-3.7], maternal diabetes (aRR 1.4; 95% CI 1.0-2.1) and a maternal age of > or =35 years (aRR 1.2; 95% CI 0.9-1.6). Second pregnancy factors included birth defects (aRR 2.5; 95% CI 1.4-4.2), placenta praevia (aRR 2.5; 95% CI 1.5-4.1) and a female infant (aRR 1.2; 95% CI 1.0-1.5)., Conclusions: The increased recurrence risk of breech presentations suggests that women with a history of breech delivery should be closely monitored in the latter stages of pregnancy.

Objective: To investigate whether changes in maternal and birth characteristics explain the increase in the use of epidural analgesia during labor., Methods: Using data from a statewide surveillance system of all births, the study included 857,667 women who labored at term between 1992 and 2003 in New South Wales, Australia. Annual rates of epidural analgesia use were calculated. Logistic regression models were used to predict epidural analgesia rates over time, and were compared with observed rates., Results: Epidural analgesia use increased from 17.2% in 1992 to 26.5% in 2003. The increase in the proportion of women with factors associated with epidural analgesia use explained almost half of the increase in rate. After controlling for these factors, the odds of a woman receiving epidural analgesia in 2003 compared with 1992 were 1.42 (95% CI, 1.38-1.46)., Conclusion: Changes in maternal or birth characteristics partially explain the increase in epidural analgesia rate. The unexplained increase may be due to increased availability or other factors.

Administrative population health data, such as hospital discharge data, are a potentially valuable resource for determining anaesthesia and analgesia use in childbirth at a population level. However the reliability of general anaesthesia reporting is unknown. This study aimed to determine the accuracy of the reporting of peripartum general anaesthesia in single and linked population health data. Data from a statewide validation study of 1200 women provided the gold standard for delivery and postpartum general anaesthesia use. The validation data were merged with both the hospital discharge and birth databases. As both of these datasets collect information on general anaesthesia, it could be reported in one, both or neither database. Among the 1184 records available for review, 7.7% of women had a general anaesthetic during the birth admission, of which 6.2% were for delivery and 1.5% were for a postpartum procedure. Reporting sensitivities ranged from 26% to 97% and specificities 94% to 100%. Identifying general anaesthesia from either the birth or hospital data improved general anaesthesia ascertainment. Limiting analysis to caesarean sections resulted in very accurate identification of general anaesthesia for delivery (sensitivity 97.0%, specificity 99.8%) while limiting to vaginal births was moderately accurate for identifying postpartum general anaesthesia (sensitivity 73.2%, specificity 99.8%). General anaesthesia for delivery is reported with a high level of accuracy in birth and linked birth-hospital data, but not in hospital discharge data alone. Population health data are a reliable source for examining general anaesthesia for delivery.

Objective: To determine whether changes in risk factors for postpartum hemorrhage (PPH) over time are associated with a rise in postpartum hemorrhage rates., Methods: Population-based study using linked hospital discharge and birth records from New South Wales, Australia for 752,374 women giving birth, 1994-2002. Analyses include a description of trends and regression analysis of risk factors for postpartum hemorrhage and comparison of predicted and observed rates of postpartum hemorrhage over time., Results: Increasing proportions of women aged 35 years or older, born overseas, nulliparous, having cesarean births, having inductions and/or epidurals, postterm deliveries and large babies were evident. Observed postpartum hemorrhage rates increased from 4.7 to 6.0 per 100 births (P<0.001) while expected rates, adjusted for covariates, remained steady (P=0.28)., Conclusion: Increases in postpartum hemorrhage are not explained by the changing risk profile of women. It may be that changes in management and/or reporting of postpartum hemorrhage have resulted in higher postpartum hemorrhage rates.

Cancer incidence in migrants to New South Wales (NSW) from individual countries within the British Isles has been compared with that in the Australian-born population using data from the NSW Central Cancer Registry for the period 1972-84. Indirectly age-standardised incidence ratios (SIR) showed that, for cancer at all sites combined, Scottish migrants had a significantly higher, and English migrants a lower, incidence than the native-born Australians. Melanoma of skin was less common in migrants from all four countries while lung cancer was more common. In all except the Irish migrants, stomach cancer was more frequent than in the Australian-born. Raised SIRs for bladder cancer were found in men from all the countries and for breast cancer in all except the Irish women but only in the English migrants were these ratios significant. English migrants differed from those from Wales, Scotland and Ireland in that, compared with the Australian-born, they had significantly lower SIRs for cancer of the colon (both sexes), head and neck, larynx and prostate (men), gallbladder and kidney (women), and a higher SIR for ovarian cancer. Bone cancer was relatively more common in men born in Wales. 'Other genital' cancers (penis and scrotum; vulva and vagina) tended to be more frequent in migrants from each country than in the Australian-born.

Cancer incidence in New Zealand born residents of New South Wales (NSW) has been compared with that in the Australian born population using data from the NSW Central Cancer Registry for the period 1972-84. Indirectly age-standardised incidence ratios (SIR) showed that New Zealand born women living in NSW had higher rates of cancer at all sites combined (SIR = 112) and a significant excess of colorectal cancer (SIR = 126). Although overall cancer rates were similar in men born in New Zealand to those in the Australian born men, the New Zealanders had a significantly higher risk of colorectal (SIR = 124) and testicular cancer (SIR = 227), cancers which are more common in New Zealand than in Australia. While the SIRs for lung cancer in men and melanoma of skin in both sexes were low, no cancer was significantly less common in New Zealand born residents of NSW than in the Australian born.

The incidence of cancer in migrants to New South Wales (NSW) from Italy, Greece, Yugoslavia, Germany, the Netherlands, Poland and USSR has been compared with that in the Australian-born population using data from the NSW Central Cancer Registry for 1972-84. The indirectly age-standardized incidence ratios (SIR) in all seven countries were low for melanoma of skin and high for gastric cancer. Cancers of the colon, oesophagus and lip also tended to have low SIRs. Migrants from Italy, Greece and Yugoslavia had significantly less cancer at all sites than the native-born Australians mainly due to low SIRs for cancers of colon, lung (except Yugoslavian-born men), prostate and, in men, 'head and neck' (excluding nasopharynx). Cancers of breast and testis were relatively less common in migrants from Italy and Yugoslavia. SIRs were high for cancers of bladder (in Italian-born men), liver (in Greek- and Yugoslavian-born men) and nasopharynx (in Greek-born men and Italian-born men and women). Amongst migrants from the four more northerly European countries, ovarian cancer was relatively more common in women from Germany and Poland as was bladder cancer in men, but not women, from Germany and the Netherlands. Cancers which had significantly increased SIRs in one migrant group only were lung (Dutch-born men), cervix uteri and body of uterus (German-born women), gallbladder and bile ducts (Polish-born women), thyroid (Italian-born women), connective and other soft tissue (Russian-born men) and brain (Greek-born men and women computed together). Lymphomas were relatively less common in men born in Yugoslavia.

Data from the New South Wales (NSW) Central Cancer Registry comprising all new cases of, and deaths from, invasive cancer of the cervix uteri registered in persons aged 15 years and over for the 10-year period 1973 to 1982 were examined using log-linear regression to determine whether incidence and mortality had been changing in NSW. Allowing for the estimated fraction of women who had undergone hysterectomy, this cancer had decreased significantly in incidence (-1.3% per year) as well as mortality (-3.6%). There were no significant trends in relation to age at diagnosis, stage at diagnosis or histological type. Overall, younger age at diagnosis was associated with an earlier stage at presentation and there was no evidence for a trend towards more severe disease in young women during the 10-year period. No evidence was found for an increasing incidence of adenocarcinoma. By 1982 the age-standardized incidence rate was 10.4 per 100,000 (12.5 per 100,000 after adjustment for the hysterectomy fraction). Cancer of the cervix uteri was more common in Inner and Western Sydney and less common in the Northern Metropolitan region of Sydney and rural New South Wales.