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Objective: Identify independent and novel risk factors for late‐preterm (28–36 weeks) and term (≥37 weeks) stillbirth and explore development of a risk‐prediction model. Design: Secondary analysis of an Individual Participant Data (IPD) meta‐analysis investigating modifiable stillbirth risk factors. Setting: An IPD database from five case–control studies in New Zealand, Australia, the UK and an international online study. Population: Women with late‐stillbirth (cases, n = 851), and ongoing singleton pregnancies from 28 weeks' gestation (controls, n = 2257). Methods: Established and novel risk factors for late‐preterm and term stillbirth underwent univariable and multivariable logistic regression modelling with multiple sensitivity analyses. Variables included maternal age, body mass index (BMI), parity, mental health, cigarette smoking, second‐hand smoking, antenatal‐care utilisation, and detailed fetal movement and sleep variables. Main outcome measures: Independent risk factors with adjusted odds ratios (aOR) for late‐preterm and term stillbirth. Results: After model building, 575 late‐stillbirth cases and 1541 controls from three contributing case–control studies were included. Risk factor estimates from separate multivariable models of late‐preterm and term stillbirth were compared. As these were similar, the final model combined all late‐stillbirths. The single multivariable model confirmed established demographic risk factors, but additionally showed that fetal movement changes had both increased (decreased frequency) and reduced (hiccoughs, increasing strength, frequency or vigorous fetal movements) aOR of stillbirth. Poor antenatal‐care utilisation increased risk while more‐than‐adequate care was protective. The area‐under‐the‐curve was 0.84 (95% CI 0.82–0.86). Conclusions: Similarities in risk factors for late‐preterm and term stillbirth suggest the same approach for risk‐assessment can be applied. Detailed fetal movement assessment and inclusion of antenatal‐care utilisation could be valuable in late‐stillbirth risk assessment. This article includes Author Insights, a video abstract available at: https://players.brightcove.net/3806881048001/default%5fdefault/index.html?videoId=6320088103112. Linked article: This article is commented on by J. Jardine, pp. 1071 in this issue. To view this mini commentary visit https://doi.org/10.1111/1471‐0528.17469. [ABSTRACT FROM AUTHOR]

Background New Zealand guidelines recommend that information regarding childbirth choices be given to women with previous caesarean, so they can make informed decisions about their care. We hypothesised that rates of trial of labour ( TOL) and vaginal birth after caesarean ( VBAC) would vary by women's ethnicity. Aim To estimate the association of ethnicity with TOL and VBAC rates. Materials and methods Clinical data were used to identify women who gave birth at Auckland Hospital in 2006-2009 with history of previous caesarean eligible for TOL. Multivariable models were used to estimate the association of women's characteristics (ethnicity, age, socio-economic status ( SES), height, body mass index, lead maternity carer, diabetes, hypertension, haemorrhage, labour induction, gestational age) with rates of TOL and VBAC. Results In the study cohort of 2400 women, the TOL rate was 39.5%; the VBAC rate was 57.4%. Pacific women were twice as likely to have TOL, while Asian and non- New Zealand European women were half as likely to have VBAC, compared with New Zealand European women. Women in more deprived areas were more likely to have TOL, but SES was not associated with VBAC rates. Women under the care of private obstetricians were least likely to have TOL or VBAC. Conclusions There are ethnic disparities in TOL and VBAC rates at our hospital. Strategies need to be developed to ensure that women of all ethnicities have access to both options for mode of delivery. [ABSTRACT FROM AUTHOR]

Background One in four New Zealand ( NZ) women undergo caesarean section ( CS); however, little is understood about how ethnicity influences CS rates. Previous NZ studies do not include many of NZ's ethnic groups and have been unable to account comprehensively for clinical risk factors. Aim To investigate ethnicity as an independent risk factor for elective and emergency CS in nulliparous women at term. We hypothesised that compared with European, Māori and Pacific women would have a lower risk of elective CS, but there would be no ethnic differences in emergency CS. Methods This was a retrospective cohort analysis of prospectively recorded maternity data at National Women's Health, Auckland, NZ from 2006 to 2009. The study population was 11 848 singleton, nulliparous, term births. Multivariable logistic regression analysis was performed for elective and emergency CS, accounting for comprehensive confounding factors. Results The overall CS rate was 31.2% (elective 7.8%, n = 923 and emergency 23.4%, n = 2770). Compared with European ethnicity, Pacific and Chinese women had a reduced odds of elective CS (adjusted odds ratios, a OR 0.42, [95% CI 0.24-0.73] and 0.68, [0.49-0.94], respectively), while Indian women had an increased odds of emergency CS ( aOR 1.54, [1.26-1.88]). Rates of elective or emergency CS for other ethnicities were similar to European. Conclusions After adjustment for confounding, we report ethnic differences in elective and emergency CS rates, which may be related to patient and/or care provider factors. Further prospective research is recommended to examine reasons for these ethnic differences in CS rates. [ABSTRACT FROM AUTHOR]

Background Infants born small for gestational age ( SGA) by customised birthweight centiles are at increased risk of adverse outcomes compared with those SGA by population centiles. Risk factors for customised SGA have not previously been described in a general obstetric population. Aim To determine independent risk factors for customised SGA in a multi-ethnic New Zealand population. Methods We performed a retrospective cohort analysis of prospectively recorded maternity data from 2006 to 2009 at National Women's Health, Auckland, New Zealand. After exclusion of infants with congenital anomalies and missing data, our final study population was 26,254 singleton pregnancies. Multivariable logistic regression analysis adjusted for ethnicity, body mass index, maternal age, parity, smoking status, social deprivation, hypertensive disease, antepartum haemorrhage ( APH), diabetes and relevant pre-existing medical conditions. Results Independent risk factors for SGA included obesity (adjusted odds ratio 1.24 [95% CI 1.11-1.39] relative to normal weight), maternal age ≥ 35 years (1.16 [1.05-1.30] relative to 20-29 years), nulliparity (1.13 [1.04-1.24] relative to parity 1), cigarette smoking (2.01 [1.79-2.27]), gestational hypertension (1.46 [1.21-1.75]), pre-eclampsia (2.94 [2.49-3.48]), chronic hypertension (1.68 [1.34-2.09]), placental abruption (2.57 [1.74-3.78]) and APH of unknown origin (1.71 [1.45-2.00]). Gestational diabetes (0.80 [0.67-0.96]) and type 1 diabetes (0.26 [0.11-0.64]) were associated with reduced risk. Conclusions We report independent pregnancy risk factors for customised SGA in a general obstetric population. In contrast to population SGA, obesity is associated with increased risk. Our findings may help identify pregnancies that require increased fetal growth surveillance. [ABSTRACT FROM AUTHOR]

Background Pre-eclampsia rates are reported to vary by ethnicity; however, few studies include body mass index ( BMI). Increasing BMI has a dose-dependent relationship with pre-eclampsia, and rates of overweight and obesity as well as ratios of body fat to muscle mass differ between ethnicities. We hypothesised that after adjusting for confounders, including ethnic-specific BMI, ethnicity would not be an independent risk factor for pre-eclampsia. Aim To assess independent pre-eclampsia risk factors in a multiethnic New Zealand population. Methods We performed a retrospective cohort analysis of prospectively recorded maternity data from 2006 to 2009 at National Women's Health, Auckland, New Zealand. After exclusion of infants with congenital anomalies and missing data, our final study population was 26 254 singleton pregnancies. Multivariable logistic regression analysis adjusted for ethnicity, BMI, maternal age, parity, smoking, social deprivation, diabetes, chronic hypertension and relevant pre-existing medical conditions was performed. Results Independent associations with pre-eclampsia were observed in Chinese (adjusted odds ratio ( aOR) 0.56, [95% CI 0.41-0.76]) and Māori ( aOR 1.51, [1.16-1.96]) compared with European women. Other independent risk factors for pre-eclampsia were overweight and obesity, nulliparity, type 1 diabetes, chronic hypertension and pre-existing medical conditions. Conclusions Contrary to our hypothesis, we report an independent reduced risk of pre-eclampsia in Chinese and increased risk of pre-eclampsia in Māori women. Prospective studies are required to further explore these relationships. Other independent risk factors are consistent with international literature. Our findings may assist clinicians to stratify risk of pre-eclampsia in clinical practice. [ABSTRACT FROM AUTHOR]

Background: Increasing rates of postpartum haemorrhage in developed countries over the past two decades are not explained by corresponding changes in risk factors and conjecture has been raised that maternal obesity may be responsible. Few studies investigating risk factors for PPH have included BMI or investigated PPH risk among nulliparous women. The aim of this study was to determine in a cohort of nulliparous women delivering at term whether overweight and obesity are independent risk factors for major postpartum haemorrhage (PPH ≥1000ml) after vaginal and caesarean section delivery. Methods: The study population was nulliparous singleton pregnancies delivered at term at National Women's Hospital, Auckland, New Zealand from 2006 to 2009 (N=11,363). Multivariable logistic regression was adjusted for risk factors for major PPH. Results: There were 7238 (63.7%) women of normal BMI, 2631 (23.2%) overweight and 1494 (13.1%) obese. Overall, PPH rates were increased in overweight and obese compared with normal-weight women (n=255 [9.7%], n=233 [15.6%]), n=524 [7.2%], p <.001) respectively. There was an approximate twofold increase in risk in obese nulliparous women that was independent of confounders, adjusted odds ratio [aOR (95% CI)] for all deliveries 1.86 (1.51-2.28). Being obese was a risk factor for major PPH following both caesarean 1.73 (1.32-2.28) and vaginal delivery 2.11 (1.54-2.89) and the latter risk was similar after exclusion of women with major perineal trauma and retained placentae. Three additional factors were consistently associated with risk for major PPH regardless of mode of delivery: increasing infant birthweight, antepartum haemorrhage and Asian ethnicity. Conclusion: Nulliparous obese women have a twofold increase in risk of major PPH compared to women with normal BMI regardless of mode of delivery. Higher rates of PPH among obese women are not attributable to their higher rates of caesarean delivery. Obesity is an important high risk factor for PPH, and the risk following vaginal delivery is emphasised. We recommend in addition to standard practice of active management of third stage of labour, there should be increased vigilance and preparation for PPH management in obese women. [ABSTRACT FROM AUTHOR]