Clinical experience with 45 pregnancies in women with Class A diabetes and 62 pregnancies in women with insulin-requiring diabetes is described. The perinatal mortality rates were 0, 16.1, and 9.3, respectively, among the Class A, insulin-requiring, and total diabetic populations. Diabetic mothers experienced significantly higher prevalences of cesarean section and ketoacidosis than did the overall population. There were no other significant differences in maternal complications. Diabetic mothers demonstrated high rates of abnormal estriol levels and relatively low rates of positive contraction stress tests. Positive contraction stress tests were highly correlated with abnormal outcome. Delivery occurred either at or after 37 weeks in 93% of the Class A and in 81% of the insulin-requiring women. In comparison to infants in the general population, those of diabetic mothers experienced significantly elevated rates of being large for gestational age, macrosomia, and hypoglycemia. Congenital abnormalities were significantly higher in the Class A, but not in the insulin-requiring population. Neonatal morbidity could not be related to maternal diabetic control and was only minimally related to gestational age.