During the early months of your baby's life, he sleeps when he is tired, it’s that simple. You can do little to force a new baby to sleep when he doesn’t want to sleep, and conversely, you can do little to wake him up when he is sleeping soundly.
Newborn babies have very tiny tummies. They grow rapidly, their diet is liquid, and it digests quickly. Although it would be nice to lay your little bundle down at bedtime and not hear from him until morning, this is not a realistic goal for a tiny baby. Newborns need to be fed every two to four hours — and sometimes more.
Sleeping “through the night”
You may believe that babies should start "sleeping through the night" soon after birth. For a new baby, a five-hour stretch is a full night. Many (but not all) babies can sleep uninterrupted from midnight to 5 a.m. (Not that they always do.) This may be a far cry from what you may have thought "sleeping through the night" meant!
What's more, some sleep-through-the-nighters will suddenly begin waking more frequently, and it’s often a full year or even two until your baby will settle into an all-night, every night sleep pattern.