A randomised trial of 45 minutes and 15 minutes incremental oxytocin infusion regimes for the induction of labour in women of high parity

Abstract

Objective: To investigate whether in women of high parity induction of labour using a regimen of intravenous oxytocin, increasing incrementally at 45 min intervals, is safer than one increasing at 15 min intervals.

Setting: University of Benin Teaching Hospital, Department of Obstetrics and Gynaecology, Benin City, Nigeria.

Design: Randomised controlled trial.

Subjects: Ninety women of parity 5 or more requiring induction of labour by infusion of oxytocin were randomly allocated to incremental increases at either 45 min intervals (experimental group) or 15 min intervals (control group).

Main outcome measures: Mode of delivery; complications of labour and delivery (uterine rupture, precipitate labour, hyperstimulation, postpartum haemorrhage, perineal tears, puerperal pyrexia); number of days spent in hospital.

Results: The 45 min incremental regimen resulted in longer induction-delivery intervals (estimate of difference in population medians 2 h, 95% confidence interval (CI) 1-4 h); less precipitate labour (odds ratio (OR) 0.09, 95% CI 0.03-0.30); less uterine hyperstimulation (OR 0.23, 95% CI 0.09-0.59); and a reduced length of hospital stay (estimate of difference in population medians 3 days, 95% CI 2-5 days). With the 45 min interval regimen there was a reduction in the occurrence of uterine rupture, postpartum haemorrhage, perineal tears and puerperal pyrexia, but these differences did not reach statistical significance.

Conclusion: For the induction of labour in women of high parity the infusion rate of oxytocin should be increased every 45 min rather than every 15 min until contractions occur three times in 10 min and this infusion rate of oxytocin is maintained until delivery.