Despite increased clinical efforts to improve glycemic control during diabetic pregnancy, the rate of congenital malformations remains increased in studies of type 1 1 12 and type 2 gestational diabetes, 7 16 whereas the situation in GDM pregnancies remains controversial, the consensus leaning toward no, or marginally increased, occurrence of congenital malformations. 13 , 17 24 This marginal incidence of congenital malformations may be related to the presence of undiagnosed type 2 diabetic women among women with diagnosed gestational diabetes (Table 41.1). Malformation rates

Type 1 DM—5%–6% congenital malformation

Type 2 DM—5%–6% congenital malformation

GDM—Background rate of congenital malformation