- To be eligible to the trial the child will need to belong to the Pelotas 2015 Birth Cohort, to be born healthy (newborns that needed intensive care after birth and with any congenital malformations will be excluded) from a single pregnancy at gestational age 37 weeks or greater, and to sleep regularly on average less than 13 hours per 24 hours (daytime and nighttime sleep) at three months of age (as reported by the mother). The information on child sleep duration per 24 hours will be gathered during the interview with mothers from the entire cohort, by means of the answer to the questions: "How many hours does the child sleep from 7pm to 7am?" and "How many hours does the child sleep from 7am to 7pm?"as well as number and duration of daytime naps, number of wake episodes during the night and how long it takes to the child to fall sleep after a nocturnal awakening.