Some babies go back to sleep on their own, but others cry, and their parents wake up. Most babies learn to sleep all night during the first year. And many babies go back to sleep easily after their nighttime feedings.
Some babies take longer to learn to sleep through the night.
Even at two years old, one child out of every five wakes up and cries most nights. The baby's personality may be a factor. Some babies are restless, and they wake easily. Others sleep soundly and for a long time. Others need less sleep, and they wake up very early in the morning.