PRETERM LABOR AND DELIVERY

Preterm birth is a major cause of perinatal morbidity and mortality. I t accounts for 5-10% of all births, and any treatment to prevent it co uld have a profound effect on neonatal outcome in both human and econo mic terms. The pathogenes sis of both term and preterm birth remain po orly understood. Our ability to predict those at risk of preterm labou r is also inaccurate, despite the creation of scoring systems, uterine activity monitoring, cervical ultrasound and several biochemical mark ers. Current drug therapies for preterm labour have not been shown in randomised controlled trials to significantly affect perinatal morbidi ty and mortality. Furthermore, most are associated with significant ma ternal or fetal side effects. Nitric oxide (NO) is a potent smooth mus cle relaxant, produced when NO synthase acts on the amino acid L-argin ine. Its presence has been demonstrated in human myometrium. We have c onducted an observational study which has suggested that glyceryl trin itrate (GTN), an NO donor, may be effective in prolonging gestation. A randomised trial comparing GTN to intravenous ritodrine is currently recruiting patients; results will be available in the Spring of 1997. Few side effects have so far been encountered. Evidence suggests that GTN, an NO donor, should be a safe and effective tocolytic and early o bservations are encouraging; randomised trials currently underway shou ld determine the significance of this breakthrough in the management o f preterm labour.