The routine use of oxytocin after oral misoprostol for labour induction in women with an unfavourable cervix is not of benefit

Abstract

Background: Induction of labour with misoprostol is often augmented with oxytocin with the possible consequence of uterine hypercontractility. It is important to determine whether the use of oxytocin in this circumstance has benefit as well as risk.

Aim: To compare two regimens for labour induction in women with an unfavourable cervix: oral misoprostol vs. oral misoprostol routinely followed by oxytocin.

Methods: A prospective randomised trial in which 200 women with an unfavourable cervix received either oral misoprostol 25 microg every 3 h (group 1, n = 100) or two such doses routinely followed by oxytocin (group 2, n = 100). Outcomes included change in Bishop score, induction delivery interval, oxytocin requirement, contraction abnormalities, mode of delivery and neonatal outcome.

Result: The improvement in Bishop score with two misoprostol doses in all 200 women was highly significant (2.9 +/- 1.5 to 6.6 +/- 1.9, P < 0.0001). The induction delivery interval, Caesarean delivery rate, vaginal delivery rate within 24 h, contraction abnormalities and neonatal outcome were similar in both groups. Contraction abnormalities were remarkably low with either regimen (1%). Routine addition of oxytocin 3 h after the second misoprostol dose (group 2) resulted in the maximum oxytocin dose (64 mU/min) being given to more women (66% in group 2; 36% in group 1).

Conclusion: There was no benefit of routine addition of oxytocin after two doses of misoprostol. Reduced oxytocin requirement was observed when it was added only if needed. Both regimens achieved 85-87% vaginal deliveries with low incidence of hypercontractility.