Melatonin, a hormone that regulates sleep-wake cycles, is not produced in significant quantities by infants immediately after birth. Newborns initially rely on melatonin received transplacentally from the mother during pregnancy, and later through breast milk, which contains melatonin especially during nighttime feedings. This external source helps establish early circadian rhythms.
The endogenous production of this crucial hormone typically begins to develop in infants at approximately three months of age. This development is gradual, and the level of hormonal production increases over the first year. This internal production plays a significant role in the consolidation of sleep patterns and the development of a more regular sleep schedule.
