Association between time of delivery and composite adverse outcomes in pregnancies complicated by diabetes

To compare the composite neonatal and maternal adverse outcomes among women with diabetes who labor and deliver at 37-41 weeks at distinct time shifts.

This population-based retrospective cohort study using the US Vital Statistics dataset on Period Linked Birth-Infant Death Data from 2013-2017. The study population was restricted to non-anomalous singleton live births from women with pregestational or gestational diabetes, who labored and delivered at 37 0/7 to 41 6/7 weeks of gestation. The time of delivery was categorized as the first shift (7:00-15:00), the second shift (15:00-23:00), and the third shift (23:00-7:00). The primary outcome was a composite neonatal adverse outcome; the secondary outcome was a composite maternal adverse outcome. Multivariable Poisson regression models were used to estimate the association between the time of delivery and adverse outcomes (using adjusted relative risk [aRR] and 95% CI).

Of 19.8 million live births during the study period, 3.3% (643,610) met the study inclusion criteria. The overall rate of composite neonatal and maternal adverse outcomes were 9.62 and 3.63 per 1000 live births, respectively. Multivariable adjusted regression analysis showed that, compared to newborns delivered at the first shift, the risk of composite neonatal adverse outcome was modestly but significantly higher (aRR 1.19, 95% CI 1.12-1.27) in the third shift (23:00-7:00). There was no significant difference in the risk of composite maternal adverse outcomes between time shifts. In the sensitivity analysis stratified by the day of the week (weekday vs weekend), the results were consistent with the primary analyses.

Among term pregnancies complicated by diabetes, compared with delivery at 7:00-15:00, the risk of a composite neonatal adverse outcome is marginally but significantly higher if delivery occurs at the third shift (23:00-7:00).