Sixty patients with diabetes mellitus (DM) antedated pregnancy were enrolled; seven had proliferative retinopathy, 13 had simple retinopathy, and 40 were intact. Diet and/or insulin was prescribed to adjust their glucose control at fasting to < 100 mg/dl, as well as at 2 hours postprandial to < 120 mg/dl. Glycohemoglobin (Hemoglobin A1c) levels ranged between 5.4% and 6.4% in the third trimester in three groups. Incidences of pregnancy complications (toxemia, hydramnios, urinary tract infection and cesarean section) and neonatal complications (low Apgar score, hypoglycemia, jaundice, polycythemia, respiratory distress syndrome and anomaly) did not differ significantly with the grade of retinopathy. Compared with the intact group, the duration of DM was significantly longer in the retinopathy groups and the incidence of fetal distress was significantly higher in the proliferative retinopathy group. In ten of 60 patients (16.7%) the grade of retinopathy progressed during pregnancy. In four patients photocoagulation was performed for neovascularization, and proved to be effective. There was a tendency for those whose retinopathy progressed to the proliferative stage during pregnancy to have larger decreases in glycohemoglobin and for their retinopathy to worsen after delivery. With tight maternal glucose control and intensive fetal surveillance, we obtained good perinatal outcome in pregnancies with diabetic retinopathy, as compared to diabetic pregnancy without diabetic microangiopathy. Careful and frequent monitoring of retinal changes should be required during pregnancy and the postpartum period.