Early versus delayed oxytocin augmentation in nulliparous women with prolonged labour--a randomised controlled trial.

OBJECTIVE To study the effects of early versus delayed oxytocin augmentation on the obstetrical and neonatal outcome in nulliparous women with spontaneous but prolonged labour. DESIGN Randomised controlled study. SETTING Two delivery units in Sweden. POPULATION Healthy nulliparous women with normal pregnancies, spontaneous onset of active labour, a cervical dilatation of 4-9 cm and no progress in cervical dilatation for 2 hours and for an additional hour if amniotomy was performed due to slow progress. METHODS Women (n = 630) were randomly allocated either to labour augmentation by oxytocin infusion (early oxytocin group) or to postponement of oxytocin augmentation for another 3 hours (expectant group). MAIN OUTCOME MEASURE Mode of delivery (spontaneous vaginal or instrumental vaginal delivery or caesarean section) and time from randomisation to delivery. RESULTS The caesarean section rate was 29 of 314 (9%) in the early oxytocin group and 34 of 316 (11%) in the expectant group (OR 0.8, 95% CI 0.5-1.4), and instrumental vaginal delivery 54 of 314 (17%) in the early oxytocin versus 38 of 316 (12%) in the expectant group (OR 1.5, 95% CI 0.97-2.4). Early initiation of oxytocin resulted in a mean decrease of 85 minutes in the randomisation to delivery interval. CONCLUSION Early administration of oxytocin did not change the rate of caesarean section or instrumental vaginal delivery but shortened labour duration significantly in women with a 2-hour arrest in cervical dilatation. No other clear benefits or harms were seen between early and delayed administration of oxytocin.