Inclusion and exclusion criteria
| Inclusion | Exclusion |
| Nulliparous | Women with indications for induction of labour (IOL) or caesarean section prior to 40 weeks and 10 days because of medical and/or obstetric complications |
| Singleton, live pregnancy | Any known fetal congenital abnormality or compromise/condition that would necessitate admission to neonatal intensive care unit after birth |
| Cephalic presentation | Women with diagnosed fetal death in utero at recruitment |
| No clinical indication for IOL at time of recruitment | Any known sensitivity or adverse reaction to melatonin or excipients in melatonin formulation |
| Awaiting onset of spontaneous labour | Fetal growth restriction (abdominal circumference or estimated fetal weight <10th centile) with abnormal dopplers |
| Not planning a scheduled birth before 41 weeks’ gestation unless subsequently indicated | Women with gestational diabetes mellitus taking metformin or insulin, or those with type I or II diabetes |
| Age 16 and over | Unable/unwilling to follow direction in participant information and consent form |
| Able to provide written informed consent to participate in the clinical trial | Unable to provide informed consent (mentally, legally, cognitively incapacitated) |
| Co-recruitment in another trial where there are competing pharmaceutical or nutritional interventions | |
| Currently taking a medication known to influence melatonin pharmacokinetics or bioavailability |