Pulsatile versus continuous administration of oxytocin for induction and augmentation of labor: two randomized controlled trials

Objective: To determine whether pulsatile oxytocin infusion improves delivery outcome in women requiring induction or augmentation of labor.

Study design: Two related randomized controlled trials undertaken in 2 inner-city United Kingdom university hospitals (ISRCTN72773405; http://www.isrctn.org/). Women were randomly assigned to a pulsatile or continuous infusion protocol.

Primary outcome: cesarean section rate (induction trial); operative delivery rate (augmentation trial).

Results: For induction, cesarean section rates were similar in women receiving pulsatile (n = 264, 38.3%) vs continuous infusion of oxytocin (n = 257; 37.7%; risk ratio, 1.01; 95% confidence interval, 0.81-1.26; P = .903), but associated with increased "infusion to time of delivery" intervals (P < .001) in the pulsatile group. For augmentation, pulsatile infusion resulted in higher operative delivery rates (70.1%, n = 251) vs continuous infusion (62.7%, n = 249; risk ratio, 1.12; 95% confidence interval, 0.99-1.27; P = .077) and increased neonatal morbidity.

Conclusion: For induction, pulsatile infusion of oxytocin is effective, but conferred little clinical benefit. Pulsatile infusion is not recommended for augmentation.