Fetal heart rate patterns and uterine activity after segmental epidural analgesia.

The effects of low-dose segmental epidural analgesia on fetal heart rate (FHR) patterns, uterine activity, and some clinical features were examined in a series of 105 normal parturients. The aim of the analgesic technique was to relieve pain during the first stage of labour by blocking the sensory nerve fibres at the spinal level of T 10 to T12, with either 0-5 per cent bupivacaine or bupivacaine with adrenaline 1 : 200 000, the dose varying from 10 to 25 mg. Obvious pathological changes (late decelerations, prolonged fetal bradycardia, variable deceleration, or loss of beat to beat variation) in FHR patterns within the first 30 minutes after the beginning of analgesia were noted in 9 per cent of the patients. Addition of adrenaline to the analgesic agent seemed to reduce uterine activity for 60 minutes after the analgesia and this was reflected in a longer interval between the block and delivery. A 25 per cent fall in systolic blood pressure was recorded in 11 per cent of the patients. Nine patients required vacuum extractions. Our results show that the epidural technique employed has distinct advantages over the previous methods, which require larger doses of the analgesic, agent, and is therefore safer for the fetus; the addition of adrenaline to the analgesic agent is contraindicated.