The management of preterm labour

Preterm labour is a major cause of perinatal mortality and morbidity. The aetiology is multifactorial and attempts to predict preterm labour are unsuccessful. At the present time prophylaxis is unhelpful and the obstetrician must manage preterm labour as it arises. The management of preterm labour remains controversial because of the difficulty in conducting good clinical trials. Antepartum glucocorticoids are effective in reducing the incidence and severity of respiratory distress syndrome. The effect is dependent upon a number of factors such as race, fetal sex, gestational age, state of the membranes, fetal asphyxia and timing of delivery in relation to therapy. Tocolytics are effective in stopping contractions but this does not produce a significant prolongation of pregnancy or reduce perinatal mortality or morbidity. It is because they can suppress contractions and delay delivery for a short time that great care should be taken that this short delay is used beneficially, e.g. in-utero transfer, or steroid therapy. It is also important that this suppression does not result in an inappropriate delay where early delivery is indicated because of infection or fetal distress. Steroids, tocolytics and antibiotics are potentially hazardous although all may benefit the fetus. The particular risks versus benefits of each form of therapy should be carefully considered for the particular presentation of each individual patient. While all these agents given antenatally are of potential benefit to the fetus and neonate, prolongation of pregnancy for its own sake or for the sake of allowing time to administer such agents is no substitute for delivery of an infant in optimum condition.