Clinical effects of epidural block during labour. A prospective study.

The aim of this study was to evaluate the clinical effects of epidural block for pain relief during labour in an obstetric unit which manages mainly high-risk pregnancies. In the majority of the 62 patients studied only 5 ml of a 0,5% solution of bupivacaine was sufficient for effective pain relief. In 75% of patients total pain relief was obtained. Complications of the procedure were hypotension in 32% of patients and bladder atony needing catheterization in 19%. The mean fall in blood pressure was greater in patients with pre-existing hypertension. The incidence of instrumental delivery was 40%, inadequate bearing-down effort being the indication in 54% of these cases. An abnormal fetal heart rate pattern on cardiotocography developed in 13 of 58 fetuses who were monitored internally, while in 3 cases an abnormal pattern because even more abnormal (in one-third of these cases this followed hypotension in the mother). The only statistically significant change in fetal heart rate patterns on cardiotocography was a decrease in the beat-to-beat variability. Epidural block is a very effective form of pain relief during labour but has potentially serious effects, especially in high-risk pregnancies. Precautions to minimize the risk of complications include the administration of intravenous fluid before the procedure and careful monitoring of the patient and her unborn baby. A cardiotocographic monitor is essential for the latter purpose.