The issue of sleep training has become rather emotional and downright nasty in recent years. The controversy centers around whether methods that advocate letting babies cry (even for short periods of time) are cruel, and whether it has negative downstream effects over the course of development. Experts that advocate no-tears methods have called parents who sleep train selfish, and some have even gone as far to call sleep training abusive. This debate has left many tired parents feeling confused about what to do, and feeling guilty for wanting their babies to sleep through the night. The big question is, does research support claims that sleep training is cruel? Is crying bad for babies? The short answer is, there isn’t much research out there on the topic, but the research that does exist might make us feel a little bit better about our decision, whether it is to sleep train our babies or not.

Uzma Jaffar/Flickr
Source: Uzma Jaffar/Flickr

The idea behind many sleep training methods is that when babies learn to rely on parent behaviors (e.g., rocking, nursing) to help them go to sleep, they don’t learn how to fall asleep by themselves and will inevitably need those same parent behaviors to help them go back to sleep if they wake up in the middle of the night. Advocates of these methods argue that babies need to learn to how soothe themselves when they wake up so that mom and dad don’t have to step in to help their babies fall back to sleep. Most of these methods will recommend putting babies to bed drowsy, but not asleep. Then many of them teach parents to gradually eliminate parent-centered methods that babies rely on like rocking or feeding in order to fall asleep, and then to slowly pull back on soothing babies when they wake up, so that babies have an opportunity to learn how to self-soothe and go back to sleep on their own.

The little evidence there is on the efficacy of sleep training suggests that it is effective. The reason why these methods recommend putting babies to bed while drowsy, but still awake, is that research shows that babies that can fall asleep on their own are the ones that are most likely to fall back to sleep on their own when they wake up again in the middle of the night, which is likely to happen at the end of each sleep cycle. In fact, one study showed that the factor most related to not sleeping for six plus hours straight was parents’ presence at the time a baby first falls asleep.

The sticking point is that removing parents’ involvement at bedtime inevitably results in some amount of crying, and some methods recommend that parents let their babies cry for a predetermined (and relatively short) period of time. It’s important to note here that many sleep training methods like the Ferber method do not advocate just putting babies in their cribs and letting them cry for hours and hours without comfort. As mentioned above, sleep training usually involves teaching parents to slowly pull back on parent-centered methods to help babies fall asleep (e.g., rocking, nursing), and to then slowly pull back on soothing in the middle of the night. Many advocates of sleep training also don’t recommend trying it before a baby is capable of developing self-soothing strategies—usually not before a baby is four to six months of age. They also don’t recommend sticking with sleep training if it doesn’t seem to be working for you or your baby within the first week or two.

Parents and experts who advocate for no-tears methods (or not sleep training babies at all) argue that letting a baby cry for even a short period of time is cruel and can be damaging to their development, causing the baby stress, an elevated heart rate, increased blood pressure, and can even be detrimental brain development. They also suggest that letting babies cry without soothing can lead to a developing mistrust of the parent, resulting in an insecure attachment quality and learned helplessness.

Despite these widespread claims of negative outcomes for babies who are sleep trained, there is no real evidence to back it up. As some researchers have pointed out, the only evidence that crying can be detrimental to infant development comes from studies on long term abuse and neglect; none of these studies look at the effect of brief periods of crying in an otherwise loving family. Sleep training generally doesn’t involve sustained crying for long periods of time—only brief and controlled periods of crying that usually doesn’t last more than a few days.

One recent study looked at children who had been sleep trained as babies five years later to see if there was anything different about these now 6-year-olds when compared to 6-year-olds that weren’t sleep trained as infants. The study found that there were absolutely no differences between these kids: Sleep trained kids were no more likely to have emotional problems, sleep problems, or attachment issues than kids that weren’t sleep trained as babies. In fact, there was nothing positive or negative about sleep training in the long-term, and kids were all sleeping well at age six whether they were sleep trained or not. This study suggests that there aren’t any negative long-term effects of sleep training, and that there aren’t any positive ones either. That means whether you choose to sleep train or not, your baby will probably be fine and eventually sleep through the night.

Despite there being no evidence of negative consequences of sleep training, there’s a lot of evidence that there are serious long-term negative consequences of sleep deprivation, including depression, inattentiveness, and marital problems. Even if you’re getting a full seven to eight hours of sleep total, research shows that waking up several times in the middle of the night (e.g., for nursing, soothing, etc.) can lead to depression-like symptoms and problems with attention as well. In fact, moderate sleep deprivation has effects that look similar to being drunk, and just like alcohol, puts you at risk for getting into a car accident. Sleep deprivation affects babies too, and in similar ways, making them cranky and possibly inhibiting their attention and learning.

Some experts will say that sleep training is the only way to go, while others will tell you it's cruel. They'll say you're denying your infants the opportunity to learn to self soothe, or instead, that you are building a relationship of distrust. Not everyone is comfortable with letting their babies cry, and I can sympathize. When we sleep trained my son Edwin, I cried just as long as he did, so the idea that parents who use these methods are selfish or careless couldn’t be further from the truth. The idea that parents who choose not to sleep train are selfish is just as ridiculous. Listening to both sides of the argument can make you feel like you can’t win; like you’re a bad parent either way.

Everyone seems to have an opinion these days about how you should put your baby to sleep—parents, grandparents, friends, relatives, experts, and even your next-door neighbor. What’s important to remember is that in the end, the only opinion that really matters is yours. Every baby is different, and every family is different; you should do what works best for your family’s needs. Reading about what experts say can make you crazy, when in fact the research suggests that you’ll probably be fine and your baby will be fine whichever way you go. No matter what method you use (or don’t use), all babies will eventually sleep through the night. And so will you.

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