Five pregnancies (type 1 DM, n=3; type 2 DM, n=2)were excluded because of incomplete data. The final analysis included 63 women with pregestational DM and a twin pregnancy and 63 controls with pregestational DM and a singleton pregnancy. To assess the effect of the type of DM, four subgroups were established. Subgroup 1 comprised women with a twin pregnancy and type 1 DM (n = 39), subgroup 2 comprised women with a twin pregnancy and type 2 DM (n = 24),subgroup 3 comprised women with a singleton pregnancy and type 1 DM (n = 39), and subgroup 4 comprised women with a singletonpregnancy and type 2 DM (n= 24).