Maternal, Obstetric and Perinatal Outcomes in Late Preterm and Term Births With Gestational Diabetes Versus Normoglycemia

To evaluate obstetric, maternal and perinatal outcomes by delivery week for pregnancies with gestational diabetes mellitus (GDM) and without diabetes. We conducted a secondary analysis of electronic medical record data from 9,696 (5.3%) GDM pregnancies and 173,323 pregnancies without any diabetes delivered at 34 to 40 weeks. Composite and individual outcomes included maternal (e.g., death, hypertensive disorders, hemorrhage); primary neonatal morbidity and perinatal mortality (e.g., death, ventilation use, sepsis, seizures, injury); secondary neonatal (e.g., shoulder dystocia, hypoglycemia); and neonatal respiratory support/morbidity from chart review. Modified Poisson regression with generalized estimating equations calculated adjusted relative risks (RR) for differences in outcome rates by GDM status and fetus at risk model for outcomes at delivery compared to ongoing pregnancies. A higher proportion of GDM pregnancies delivered at each week prior to 39 weeks compared to no diabetes ( 2.5%, 3.9%, 7.4%, 17.2%, 32% and 36.9% for GDM and 1.4%, 2.3%, 5.0%, 11.0%, 24.6% and 38.4% for no diabetes, at 34, 35, 36, 37, 38 and 39 weeks, respectively, P<.001). Among GDM, compared to ongoing pregnancy, risk of maternal composite was higher for delivery at 37 weeks, 20.5% vs 11.6% (RR 1.71; 95%CI 1.51-1.92) and 38 weeks, 14.9% vs 9.4% (RR 1.62; 95%CI 1.42-1.84) driven by hypertensive disorders (18.3% at 37 and 23.5% at 38 vs 10.1% at 39 weeks); and risk of primary neonatal composite was higher at 37 weeks, 2.3% vs 1.1% (RR 2.00; 95%CI 1.33-3.00). Risk of stillbirth was higher at 37 weeks, 0.41% vs 0.11% (RR 3.62; 95%CI 1.22-10.75) among GDM suggesting it was an indication for earlier delivery. For GDM-complicated pregnancies, earlier delivery at 37 and 38 weeks compared to ongoing pregnancy was associated with higher risk of maternal morbidity likely due to having hypertensive disorders, and delivery at 37 weeks with higher risk for serious neonatal morbidity.