An analysis of diabetic pregnancies at Mayo Clinic, 1950-79.

We reviewed the records of pregnant diabetic women attended at Mayo Clinic during the years 1950-79 and matched each nonaborted diabetic pregnancy with two control pregnancies. Abortions occurred in 49 of 277 diabetic pregnancies (17.7%). The relative risk of other adverse outcomes of pregnancy (+/- 95% confidence interval) in comparison with controls was as follows: perinatal mortality, 7.0 (3.6-13.8); major congenital birth defects, 6.3 (2.8-14.2); and respiratory distress, 9.0 (4.5-17.9). Diabetic ketoacidosis resulted in fetal death in 5 of 18 cases. Patients with mean fasting blood glucose levels of less than or equal to 140 mg/dl had a perinatal mortality of 81 per 1000 births and an incidence of respiratory distress and congenital birth defects of 18.9% and 9.9%, respectively. Patients with mean blood glucose levels greater than 140 mg/dl had corresponding rates of 306 per 1000, 20.4%, and 11.2%, respectively. Hydramnios occurred almost exclusively in diabetic women, and its presence was associated with a twofold increase in the frequency of perinatal death. Analysis of diabetic pregnancy outcome by decade showed no appreciable decrease in the occurrence of perinatal mortality, congenital birth defects, or respiratory distress over the 30-yr period.