Epidural analgesia and placental blood flow during labour in pregnancies complicated by hypertension.

Placental blood flow was measured during the first stage of labour in pregnancies complicated by essential hypertension or severe pre-eclampsia using a 133Xe clearance technique before and after segmental epidural analgesia. Analgesia was produced with 0.5 per cent plain bupivacaine in six patients with essential hypertension and in 11 patients with severe pre-eclampsia. After segmental epidural analgesia the placental blood flow was slightly but insiginificantly improved in most of the patients with pre-eclampsia and in half of the patients with essential hypertension, thus suggesting this analgesic method to be safe in hypertensive pregnancies in the absence of any substantial change in systemic blood pressure.