Pulsed Doppler ultrasound assessment of blood flow was performed in the fetal aorta and umbilical arteries of 41 patients with hypertension in pregnancy. Patients were grouped according to severity of the hypertension and the presence or absence of chronic hypertension. Doppler abnormalities were seen in two patients with chronic hypertension, both of whom delivered small for gestational age infants. Only one patient with mild to moderate preeclampsia had abnormal aortic Doppler assessment and was also delivered of a small for gestational age infant. The highest number of abnormal Doppler waveforms in both fetal aorta and umbilical artery were found in patients with severe preeclampsia. Abnormalities were detected more frequently in the fetal aorta than in the umbilical artery. Doppler assessment was often abnormal before a nonstress test or biophysical profile. The number of abnormal Doppler values correlated with perinatal outcome in patients with severe preeclampsia.