Parents often think this method of sleep training involves leaving babies alone to cry for as long it takes before they fall asleep. But cry it out simply refers to any sleep-training approach that says it's fine to let a baby cry for a specified, usually short, period of time before offering comfort.
The theory goes that without a rewarding response to his cries, a baby learns that it's not worth the trouble to cry so hard. Richard Ferber, author of Solve Your Child's Sleep Problems, is the best-known advocate of this tactic.
He says most babies should be sleeping through the night by the time they are three or four months old. If your baby isn’t having a settled night’s sleep by the time he is about four months, steps can be taken to address the problem:
Put your baby in his cot when he is still awake, perhaps a little later than his usual bedtime to start off with, so he’s properly tired. If he cries, go to him only at set intervals, and reassure him, without turning on the lights or picking him up.
On the first night of the routine, these intervals can start off being three, then five, then 10 minutes long. Over a week, the intervals can be extended, gradually reaching 20 minutes to half an hour after seven days.
When you go in to your baby, says Ferber, make sure he's not twisted up in his blankets or without his favourite stuffed animal, speak comfortingly to him and leave the room. Don’t stay in the room for more than a minute or two. If he throws his toy or blanket out of his cot between your timed visits, leave it until the interval ends to put it back.
Eventually, your baby will learn to fall asleep on his own.
One study found that babies who were at least seven months old who were left for short periods to cry it out experienced no marked long-lasting effects. This may help to reassure you that short spells of crying it out won't harm your baby.
However, Ferber does caution that no single approach works for every baby. The American Academy of Sleep Medicine reviewed sleep-training strategies, including crying it out. The conclusion was that there's no single, best approach for solving your baby's sleep problems. All the methods work, provided you follow one simple rule: consistency.