Melatonin production in infants: Association with perinatal factors and development

This study investigated the relationships of the excretion of the melatonin metabolite, 6-sulfatoxymelatonin, to prenatal, natal, and postnatal variables and its possible relation to psychomotor development. Nocturnal urinary excretion of 6-sulfatoxymelatonin was studied over a 13-hour period in 355 term infants at 8 weeks of age (n = 320) and 16 weeks of age (n = 96). Data on a variety of perinatal factors including pregnancy course, delivery, early postnatal course, birth weight, medical problems, growth (length, weight, and head circumference), and psychomotor development were collected at 1, 3, 6, 9, 12, and 18 months. The relationship between nocturnal 6-sulfatoxymelatonin excretion at 8 and 16 weeks of age and these factors was investigated and analyzed. 6-Sulfatoxymelatonin levels at 16 weeks of age were significantly lower in infants with abnormal vs normal development at 3 months of age (7.27 + 1.44 vs 7.97 + 1.06, p = 0.05) as well as at 6 months of age (7.15 + 1.29 vs 7.95 + 1.10, p = 0.04). No other significant relation was evident among growth, perinatal complications, medical problems, and 6-sulfatoxymelatonin excretion at 8 weeks of age and at 16 weeks of age. Low melatonin excretion in the first weeks of life correlates with delayed psychomotor achievements at 3 and 6 months of age. This association suggests a causal or predictive link between melatonin and neurodevelopment in infants.