Double-blind, randomised, placebo-controlled trial to evaluate the effectiveness of late gestation oral melatonin supplementation in reducing induction of labour rates in nulliparous women: the MyTIME study protocol.

Introduction: Around the world, rates of induction of labour (IOL) among nulliparous mothers have increased in the last 10 years. In Australia, rates have increased over the last decade by 43%, from 32% to 46%. There is growing concern about the rapid rise in IOL before 41 weeks for nulliparous women without medical complications because of the associated increased rates of caesarean section, reduced satisfaction with birth, and birth trauma. Melatonin potentiates the action of oxytocin and may promote the spontaneous onset of labour; therefore, we will test the hypothesis that exogenous melatonin supplementation in late pregnancy will reduce the rate of labour induction by 30% or more.

Methods And Analyses: This is a double-blind, randomised, placebo-controlled trial in nulliparous pregnant women to reduce IOL rates. We will randomise 530 women to receive either 3 mg oral melatonin or placebo daily from 39 weeks' gestation until they give birth. The primary endpoint will be IOL rate after 39 weeks post enrolment. Secondary endpoints will include the following: interval between administration of trial medication and birth; a range of maternal and neonatal outcomes, including birth outcomes; breastfeeding on discharge, at 10 days and at 2 months; maternal satisfaction; child developmental outcomes at 2 months of age; and cost-effectiveness of melatonin compared with standard care. All data will be analysed by intention to treat.

Ethics And Dissemination: The study is approved by the Western Australia Health Central Human Research Ethics Committee (RGS0000006283). Trial findings will be disseminated through conference presentations and peer-reviewed publications.

Trial Registration Number: The trial has been prospectively registered on the Australian New Zealand Clinical Trials Registry as ACTRN12623000502639 on 17/05/2023.