Pregnancy Outcomes in Diabetes Subtypes: How Do They Compare? A Province-based Study of Ontario, 2005-2006

Objective: To ascertain differences in pregnancy outcomes between women with diabetes subtypes (type 1 [DM1], type 2 [DM2], women with gestational [GDM])] and non-diabetic women within a large Canadian population. Methods: We performed a retrospective multi-cohort analysis of all obstetrical deliveries that occurred in the province of Ontario between April 1, 2005, and March 31, 2006. Data were extracted from the Ontario Niday Perinatal Database. Results: Increased rates of major negative maternal and perinatal outcomes (i.e. preterm delivery, Caesarean section, pregnancy-induced hypertension/preeclampsia) occurred in women with DM1. Both DM1 and GDM subtypes were associated with the greatest risk of macrosomia, shoulder dystocia, and congenital anomalies. DM2 did not demonstrate an association with an increased risk of congenital malformations and stillbirth. Conclusion: Diabetes in pregnancy, irrespective of subtype, predisposes women to poorer outcomes than those of the general obstetric population. However, this large population analysis is consistent with previous studies in showing that the adversity remains greatest for women with type 1 diabetes.