Samantha L. Hocking

Background/aims To evaluate maternal birth and neonatal outcomes among women with gestational diabetes mellitus (GDM), but without specific medical conditions and eligible for vaginal birth who underwent induction of labour (IOL) at term compared with those who were expectantly managed. Materials and methods Population‐based cohort study of women with GDM, but without medical conditions, who had a singleton, cephalic birth at 38–41 completed weeks gestation, in New South Wales, Australia between January 2010 and December 2016. Women who underwent IOL at 38, 39, 40 weeks gestation (38‐, 39‐, 40‐induction groups) were compared with those who were managed expectantly and gave birth at and/or beyond the respective gestational age group (38‐, 39‐, 40‐expectant groups). Multivariable logistic regression analysis was used to assess the association between IOL and adverse maternal birth and neonatal outcomes taking into account potential confounding by maternal age, country of birth, smoking, residential location, residential area of socioeconomic disadvantage and birth year. Results Of 676 762 women who gave birth during the study period, 66 606 (10%) had GDM; of these, 34799 met the inclusion criteria. Compared with expectant management, those in 38‐ (adjusted odds ratio (aOR) 1.11; 95% CI, 1.04–1.18), 39‐ (aOR 1.21; 95% CI, 1.14–1.28) and 40‐ (aOR 1.50; 95% CI, 1.40–1.60) induction groups had increased risk of caesarean section. Women in the 38‐induction group also had an increased risk of composite neonatal morbidity (aOR 1.10; 95% CI, 1.01–1.21), which was not observed at 39‐ and 40‐induction groups. We found no difference between groups in perinatal death or neonatal intensive care unit admission for births at any gestational age. Conclusion In women with GDM but without specific medical conditions and eligible for vaginal birth, IOL at 38, 39, 40 weeks gestation is associated with an increased risk of caesarean section.