Some of these experts think cry it out methods are not good for babies. Pediatrician and "attachment parenting" advocate William Sears devotes an entire chapter of The Baby Sleep Book to a critique of cry it out approaches. Sears, along with no tears advocates such as Elizabeth Pantley (author of The No-Cry Sleep Solution), believes that cry it out techniques can give your child negative associations with bedtime and sleep that could last a lifetime.
Honestly, in our personalized consultations, we try to avoid this method as much as possible. If you are going to use cry it out, we recommend your baby is at least 6 months old, but preferably 10 months or older, when we expect almost all babies to be able to get through the night without a feeding. It is not for the faint at heart. We find that laying a foundation in the beginning with other strategies and techniques can reduce crying even if this method is used in the end, however.
Sleep experts who support the cry it out approach (as well as most pediatricians) disagree. They say it isn't traumatic for babies to cry alone for short periods of time with frequent check-ins by Mom or Dad – and the end result is a well-rested, happier child. They say no tears sleep strategies may cause babies to be overly dependent on comfort from a parent at bedtime, making it harder for them to learn to soothe themselves to sleep.
The biggest reason why the solutions that work for one parent don’t work for another is simple. They’re not dealing with the same baby. Some babies are heavily reliant on sleep props. Others can’t sleep in a room that’s too warm. Some may not be getting enough daytime sleep, and others might be overtired. This baby might have developed an association between feeding and falling asleep, whereas that one might be ready to drop their second daytime nap. And, of course, it could be any combination of all of the above, or the many other sleep challenges that babies might experience.
Proponents of these sleep training methods say it's okay for your child to cry when you put him to bed and leave the room, although they don't advocate letting a baby cry indefinitely. Typically, these methods suggest putting your baby to bed when he's still awake and allowing short periods of crying punctuated by comforting (but not picking up) your child.
The most well known cry it out technique is the one developed by pediatrician Richard Ferber, director of the Center for Pediatric Sleep Disorders at Children's Hospital Boston. Ferber says that in order to fall asleep on their own and sleep through the night, babies have to learn to soothe themselves. Ferber believes that teaching a baby to soothe himself may involve leaving him alone to cry for prescribed periods of time.
Most sleep coaches say the ideal time to start sleep training (or promote independent sleep, not necessarily using the cry-it-out method) is based on your baby’s development, but is usually somewhere between four and six months, when your baby hasn’t had much time to get used to nursing or rocking to sleep. At this stage, most babies are also developmentally ready to learn the skill of falling asleep on their own, explains Jennifer Garden, an occupational therapist who runs Sleepdreams in Vancouver. Around four months of age, some babies go through a sleep regression because their sleep cycles change and there are longer periods of lighter sleep per cycle. “It’s a great time to work on independent sleep skills,” says McGinn. Other babies’ slumber derails around this time because they are working on new skills, like moving around and rolling. Some parents choose to wait until things settle down before embarking on a sleep-training method, but you don’t have to, says McGinn.