Before the advent of insulin, few diabetic women lived to childbearing age. Before 1922, fewer than 100 pregnancies in diabetic women were reported, and most likely these women had type 1 and not type 2 diabetes. 1 Even with this assumption, these cases of diabetes and pregnancy were associated with a >90% infant mortality rate and a 30% maternal mortality rate. As late as 1980, physicians were still counseling diabetic women to avoid pregnancy. This philosophy was justified because of the poor obstetric history in 30%–50% of diabetic women. Improved infant mortality rates finally occurred after 1980, when treatment strategies stressed better control of maternal plasma glucose levels, and once self-monitoring blood glucose (SMBG) and glycosylated hemoglobin (A1C) became available. As the pathophysiology of pregnancy complicated by diabetes has been elucidated, and as management programs have achieved and maintained near-normal glycemia throughout pregnancy complicated by type 1 diabetes, perinatal mortality rates have decreased to levels seen in the general population. This review is intended to help the clinician understand the increasing insulin requirements of pregnancy and to design treatment protocols to achieve and maintain normoglycemia throughout pregnancy.