Obesity and pregnancy outcomes: Do the relationships differ by maternal region of birth? A retrospective cohort study.

BACKGROUND: We aimed to determine whether the association between obesity and a range of adverse maternal and perinatal outcomes differed in South Asian and Australian and New Zealand born women.

METHODS: A retrospective cohort study of singleton births in South Asian (SA) and Australian/New Zealand (AUS/NZ) born women at an Australian hospital between 2009 and 2013. The interaction between maternal region of birth and obesity on a range of maternal and perinatal outcomes was assessed using multivariate logistic regression.

RESULTS: Obesity was more strongly associated with gestational hypertension/Preeclampsia/HELLP and Gestational Diabetes Mellitus in AUS/NZ born women (p = 0.001 and p < 0.001, respectively for interaction) and was only associated with shoulder dystocia in SA born women (p = 0.006 for interaction). There was some evidence that obesity was more strongly related with admission to NICU/Special care nursery (SCN) (p = 0.06 for interaction) and any perinatal morbidity (p = 0.05 for interaction) in SA born women.

CONCLUSIONS: Interventions targeted at reducing maternal obesity will have different impacts in SA compared to AUS/NZ born women.