 [ Symptoms ] why is not my baby sleeping through the night [ Disease ] is your baby sleeping through the night it is the question every parent of a newborn gets how well does he or she sleep at night and every new parent asks the other related question when will my baby sleep through the night ever never  no two babies are alike that is true when it comes to sleep as well i have heard from parents whose babies sleep well like a baby — through the night — as early as six weeks old and then there are those parents who still struggle to get a full night of uninterrupted sleep more than a year after their baby is birth what gives in the first few weeks of life babies do not have a circadian rhythm going yet which helps them to know the difference between daylight and nighttime this rhythm or body clock starts ticking at around six weeks of age but what is more critical to the sleep rhythms of infants is their need for nourishment in other words it is not so much that babies are missing the “on” and “off” switch that adults have when it comes to day and night cycles it is that babies cannot hold enough food i e breast milk or formula in their bellies to get through the night without needing more calories for growth it takes a baby a few months to grow a belly big enough to accommodate enough calories so they may rest for longer periods without needing to fill up again and because breast milk in particular gets digested more quickly than formula moms who exclusively breastfeed typically find themselves tending to their tots more frequently than those who are formula fed but here is some good news for new parents who worry that they may be doomed to years of sleeplessness a new study published in the journal pediatrics and done by researchers from the university of canterbury new zealand states that by the age of 5 months over 50 percent of all infants are following their parents sleeping times — and sleeping right through the night sound too good to be true well this also means that 50 percent of infants are not following their parents sleeping schedules and are not sleeping through the night there is a difference between a baby matching his or her parents sleeping schedule and sleeping “through the night ” the researchers noted that achieving non stop sleep does not take that long but its coinciding with the parents schedule takes longer for example a baby who sleeps for six straight hours but does so from 6 pm to midnight is not going to please most parents who would prefer to go to bed at 10 and get up at 6 but a baby who sleeps for six straight hours from say 11 p m to 5 a m may be a lot easier to handle than a baby who has a parent or both up in the dead middle