A retrospective review was conducted of all women with diabetic pregnancies admitted in diabetic ketoacidosis (DKA) to hospitals affiliated with the State University of New York at Buffalo between 1980 and 1990. The experience was combined with a literature review of similar patients described between 1970 and 1990, for a total of 37 admissions for DKA during pregnancy. Emesis and the use of beta-sympathomimetic drugs were considered etiologic in 57% of cases, while patient noncompliance and physician management errors were considered etiologic in 24% and contributory in 16%. Thirty percent of patients admitted with emesis had a prepregnancy history of diabetic gastroenteropathy, thus identifying that group as at particularly high risk for DKA. In the context of modern management, the causes of DKA in pregnancy are related uniquely to pregnancy, and the disorder is largely preventable during pregnancy.