The charts of all diabetic women and their infants delivered during the years 1983-1988 in our department were reviewed. The test group included consecutive gestational diabetic women class A1 (n = 65) and class A2 (n = 59), who delivered beyond 40 weeks of gestation. The mean gestational age at delivery was 40.90 weeks (range, 40.0 to 42.57) in class A1 and 40.49 weeks (range, 40.0 to 42.28) in class A2 patients. The first control group matched for age, parity, and presentation included 65 gestational diabetic patients class A1 and 59 A2 who delivered prior to 40 weeks' gestation. The second control group matched for age, parity, and presentation included 124 nondiabetic patients who delivered beyond 40 weeks of gestation (mean, 41.04 +/- 0.83 weeks). By allowing the pregnancies of gestational diabetic patients class A1 and class A2 to proceed beyond 40 weeks of gestation, we did not increase the incidence of perinatal mortality and morbidity rate. The cesarean section rate was low (10.76% in class A1 and 22.03% in class A2). We suggest that not only elective intervention prior to 40 weeks of gestation is to be avoided, but an attempt should be made to allow the gestational diabetics class A1 and class A2 to proceed to spontaneous labor.