Amniotomy and early oxytocin infusion vs amniotomy and delayed oxytocin infusion for labour augmentation amongst nulliparous women at term: A randomised controlled trial

Objective: to compare the effect of amniotomy with early vs delayed oxytocin infusion on successful vaginal delivery.

Design: randomised controlled trial of nulliparous women with spontaneous labour at term.

Setting: labour suite of a university teaching hospital in Kuala Lumpur, Malaysia.

Participants: 240 women were included (120 randomised into two arms).

Interventions: the randomisation sequence was generated using a computer randomisation program in two blocks: oxytocin infused early following amniotomy; and oxytocin infused 2 h after amniotomy.

Measurements and findings: labour duration, mode of delivery, oxytocin dosage used, uterine hyperstimulation, postpartum haemorrhage, Apgar score and admission to the neonatal intensive care unit were recorded. No differences in vaginal delivery rate (62.9% vs 70.9%; p = 0.248) and second-stage labour were found between the early and delayed oxytocin infusion groups (21.2 ± 18.3 min vs 25.5 ± 19.9 min; p = 0.220). The mean interval from amniotomy to vaginal delivery was significantly shorter for the early group (5.8 ± 1.7 h vs 7.0 ± 1.9 h; p = 0.001), and more women in the early group delivered during/before the planned review at 4 h after amniotomy (53.6% vs 10.6%; p<0.001). Maximum oxytocin usage was lower in the early group (5.6 ± 4.4 mL/hour vs 6.8 ± 5.3 mL/hour; p = 0.104).

Key conclusions: early oxytocin augmentation following amniotomy could be employed in low-risk primigravida, given that it is associated with a shorter labour duration without jeopardising maternal or neonatal outcomes.

Implications for practice: low-risk primigravida benefit from early oxytocin infusion following amniotomy, and this can be offered as an additional practice in labour room care.