THE INHIBITORY EFFECT OF ETHANOL ON THE RELEASE OF OXYTOCIN DURING PARTURITION IN THE RABBIT

Abstract

SUMMARY The effect of ethanol on parturition was studied in conscious unrestrained rabbits fitted with intra-uterine balloons. The onset of labour was predicted by an oxytocin sensitivity test. With blood ethanol concentrations of 0·25–0·35 g./100 ml., the onset of labour was inhibited, typical contractions were absent, delivery was prolonged, abnormal and postponed for about 30 hr. With a blood concentration of 0·2 g./100 ml., labour contractions were less intense than normal and delivery was prolonged. At a lower concentration, 0·14 g./100 ml., parturition was apparently normal. Uterine sensitivity to exogenous oxytocin was unimpaired by ethanol treatment. The interference with parturition by ethanol is attributed to central inhibition of the abrupt reflex release of oxytocin.