Effect of Continuous Nerve Block of the Uterus on Stretch-Induced Uterine Activity in the Mid-Trimester

Summary

The possible roles of endogenous oxytocin, and spinal reflex mechanisms of the autonomic nerves were studied after the induction of abortion in the mid-trimester by uterine stretching. A complete epidural and caudal block of the afferent nerves from the uterus was performed before the insertion of laminaria tents or a balloon into the uterus, and this nerve block was maintained throughout the study. Uterine activity showed no significant difference between the nerve block and non-nerve block groups (P = 0 71), but differed significantly with increasing time after stretching (P < 0 001). Plasma oxytocin values did not increase significantly in either the normal or the nerve-blocked patients.