Hypertension during pregnancy in insulin-dependent diabetic women. Insulin-dependent diabetic patients are at increased risk for hypertensive disorders of pregnancy. This study was designed to study prospectively the rate of pregnancy-induced hypertension (PIH) in 175 insulin-dependent diabetic pregnancies (88 White classes B-C, 87 classes D-RT). Pregnancy-induced hypertension was defined as two or more occurrences after 20 weeks' gestation of a mean arterial pressure (MAP) of 105 mmHg or greater or an increase of 20 mmHg or greater from the baseline MAP. The rate of PIH in the diabetic population was 15.4% and was significantly associated with nulliparity, poor glycemic control in the first and second trimesters, and advanced White class. Neonatal outcome was not significantly altered in the presence of PIH. We speculate that improved glycemic control throughout pregnancy might reduce the rate of this complication in diabetic patients. 