Start of induction of labour with oxytocin in the morning or in the evening. A randomised controlled trial.

OBJECTIVE: The objective of this study was to compare outcomes of induced labour with intravenous oxytocin with a start in the evening versus in the morning.

DESIGN: Randomised controlled trial.

SETTING: Labour wards of three hospitals in Amsterdam, the Netherlands.

PARTICIPANTS: Women with an indication for induction of labour with intravenous oxytocin.

METHODS: Included women were randomized to either the evening group with a start of induction of labour at 21:00 hours, or the morning group with a start at 07:00 hours.

MAIN OUTCOME MEASURES: Primary outcome was duration of labour. Secondary outcomes were instrumental delivery rate, adverse neonatal outcome defined as an Apgar score below 7 after 5 minutes, number and indications of paediatric consults and neonatal admissions, duration of second stage, number of intrapartum infections and necessity of pain relief.

RESULTS: We randomised 371 women. Mean duration of labour was not significantly different (primiparae: morning 12 hours and 8 minutes versus evening 11 hours and 22 minutes, P value 0.29; multiparae: morning 7 hours and 34 minutes versus evening 7 hours and 46 minutes, P value 0.70). There were no significant differences in instrumental deliveries rates, number of infections or patient satisfaction. Unexpectedly, neonatal outcome was better in women induced in the evening.

CONCLUSION: Induction of labour with intravenous oxytocin in the evening is equally effective as induction in the morning.