Ye'elah Berman1,2, Ibinabo Ibiebele1,3, Jillian A Patterson1,3, Deborah Randall1,3, Jane B Ford1,3, Tanya Nippita1,3,4, Jonathan M Morris1,3,4, Miranda L Davies-Tuck5,6, Siranda Torvaldsen1,3,7. 1. The University of Sydney Northern Clinical School, Women and Babies Research, St Leonards, New South Wales, Australia. 2. NSW Biostatistics Training Program, NSW Ministry of Health, Sydney, New South Wales, Australia. 3. Northern Sydney Local Health District, Kolling Institute, New South Wales, Australia. 4. Department of Obstetrics and Gynaecology, Royal North Shore Hospital, Northern Sydney Local Health District, Sydney, New South Wales, Australia. 5. The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia. 6. Consultative Council on Obstetric and Paediatric Mortality and Morbidity, VIC Department of Health, Melbourne, Victoria, Australia. 7. School of Public Health and Community Medicine, UNSW, Sydney, New South Wales, Australia.
Abstract
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.
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.