Yes. Multiple studies have shown that sleep training is both safe and effective, without any studies showing evidence of harm. The best long-term study followed 326 children for the first six years of life. The authors reported that children who had sleep trained via any method in infancy slept better at 2 years of age than children who were not sleep trained, and their mothers were less likely to be depressed. Several years later, the researchers looked at these children again and noted that there was no evidence of emotional or behavioral problems in children who had been sleep trained versus those who had not. As part of this follow-up, the researchers measured the children’s levels of the stress hormone cortisol, which is frequently cited by opponents of sleep training as the mechanism by which crying affects developing brains. The researchers did not find any evidence of differing levels of cortisol secretion between children who had been sleep trained and those who had not.
In the first several weeks of life, babies are hungry at night, leading to an apparent reversal of day and night and erratic sleep patterns. Fortunately, this usually resolves by about 3 weeks of age, after which your child settles into a three- or four-hour cycle, typically following a pattern of waking, feeding and sleeping. At this point, exposing your baby to natural light during the day can help encourage longer periods of daytime wakefulness and more sleep at night.
Some experts suggest techniques that are slightly different than these methods. Perhaps the best known is pediatrician Harvey Karp, author of The Happiest Baby on the Block. His method suggests a very specific routine involving the so-called five S's: swaddling, the side or stomach position (for calming your baby, not for sleeping), shushing, swinging, and sucking.
Prepare yourself for a few difficult nights. Hearing your baby cry can be excruciating, as every parent knows. During the waiting periods, set a timer and go to a different part of the house, or turn on some music, so you don't have to hear every whimper. As one BabyCenter parent says, "The first week could be rough. Try to relax and know that when it's all over, everyone in your household is going to sleep more easily and happily."
But when he was about three-and-a-half months old, the routine fell apart. “I would feed him, but he wouldn’t be asleep at the end of the feed,” recalls Welk. “I would rock him until he fell asleep and put him down, and then he would wake up 30 minutes later and I would do it all over again.” Desperate for some rest, Welk brought Greyson into bed with her, but then she ended up just lying still, holding a pacifier in his mouth all night long. “I didn’t know anything about sleep,” says Welk. “I didn’t know you couldn’t just rock them to sleep and then put them down.”