Objective: To compare the efficacy of low dose vaginal misoprostol and dinoprostone vaginal gel for induction of labour at term.
Design: A single-blind randomised controlled trial.
Setting: Antenatal and labour ward of a UK district general hospital.
Participants: Two hundred and sixty-eight women requiring induction of labour at term (>37 weeks of gestation) with no significant fetal or medical condition, no previous uterine surgery and no contraindication to prostaglandin.
Methods: Misoprostol 25 microg (one-quarter of a 100 microg tablet) was inserted into the posterior vaginal fornix every 4 hours (to a maximum of six doses) or dinoprostone vaginal gel 1-2 mg 6 hourly (maximum of 3 mg in 24 hours).
Main outcome measure: Induction-to-vaginal delivery interval.
Secondary outcome measures: Requirements for oxytocin, mode of delivery, number of women delivering < 24 hours, incidence of uterine contraction abnormalities, incidence of abnormal cardiotocograph (CTG) recordings, 5-minute Apgar scores, umbilical cord pH recordings, analgesia requirements, admission to NICU and blood loss at delivery.
Results: There were no significant differences between the two groups in induction-to-vaginal delivery interval, mode of delivery, number of women delivering within 24 hours and neonatal outcomes. The incidence of uterine contraction abnormalities (tachysystole and hyperstimulation) and the incidence of abnormal CTG recordings were also similar for both groups.
Conclusion: Low dose vaginal misoprostol is as effective as dinoprostone gel for inducing labour at term. There would be substantial cost savings, estimated at around 3.9 million UK pounds per annum, for maternity services if low dose misoprostol became the agent of choice for inducing labour in the UK.