- Objective To examine pregnancy outcomes associated with diet-controlled gestational diabetes mellitus (GDM A1). Methods A retrospective cohort study compared pregnancy characteristics of women with and without GDM A1 at a center where GDM A1 patients are routinely induced at 40 weeks. Results Higher rates of complications such as shoulder dystocia, congenital malformation, and macrosomia were observed in GDM A1 patients. A lower incidence of perinatal mortality was present in GDM A1 women compared with women without GDM A1. This association lost its significance when controlled for maternal age, ethnicity, induction, cesarean delivery, and birth weight in a multivariate model. Although the stillbirth rate before 40 weeks of gestation was identical among all participants, after 40 weeks it was significantly higher in women without GDM A1. Conclusion Induction of women with GDM A1 at 40 weeks may play a role in lowering perinatal mortality to below that of the general population.