The lowdown on sleep regressions

Short answer: Sleep regressions are real, but the numbered ones are not. Sleep does get worse for a few weeks at a time, yet everything that causes it — nap transitions, crawling, walking, teething, starting daycare, a new sibling — happens across a range of many months, and the longitudinal sleep research shows no bump at 4, 6, 8 or 12 months. Do not spend your energy identifying which regression this is; deal with what your own baby is actually doing, and avoid building a long-term habit to solve a short-term phase.

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Is there a 6-month sleep regression? What are sleep regressions anyway? What causes them and how to deal with them?

Transcript:

What is a sleep regression?

Today's question seems simple enough. It is "What is the 6-month sleep regression?" So let's talk about sleep regressions. First of all, I would like to read from my book, from chapter four, which is Sleep Science 101. In this chapter, you can learn everything you need to know about sleep phases, sleep cycles, the development of sleep, sleep regressions, and sleep associations. So let me read the subchapter about sleep regressions first.

Sleep regressions are periods in the life of babies when their sleep gets worse or goes back to how it was several months before. Some of these changes are caused by the maturation of sleep itself; others are caused by other developmental changes that can affect sleep. These tend to happen around the same ages for most babies, give or take a month. Sleep goes through developmental changes just like movement, from rolling over through crawling to walking, or speech, from cooing through babbling to words. There are phases of rapid change when there is especially a lot going on in terms of sleep development. Sometimes these phases are associated with the worsening of sleep, like in the case of the 4-month sleep regression.

Another reason why sleep can get worse is that your baby is going through a nap transition. It happens before babies drop a nap, like going from napping 3 times a day to napping 2 times a day. This is exactly what might contribute to the 9-month sleep regression. Your baby might not be sleepy enough to nap 3 times, but with 2 naps, there's just too much awake time between naps and they get overtired and cranky. This, in turn, can ruin nighttime sleep too. In this case, you can help your baby by an earlier bedtime when there are less naps, so that the overall sleep during the whole day doesn't decrease that much.

Developmental changes like learning to roll over, crawling, sitting up, standing up, teething, separation anxiety could also affect sleep. This can also contribute to the 9-month sleep regression. Babies might not be able to sleep well because either they are too busy practicing their new skills, or they are too wired to settle down. The 11-month sleep regression can be a tricky one because two things can happen around the same time: babies transition to 1 nap a day and they learn to walk. Learning to walk can make them more tired, so sometimes if they transition to 1 nap just a few weeks before, they might want to go back to 2 naps again.

Growth spurts, when your baby grows a lot in a short period of time, can be a reason for frequent night feedings and night wakings too. Your baby needs more nutrition than usual during these periods, so they get hungry more often. Feed your baby as often as needed, but this period should not be longer than a week or two. Sleep is affected by outside factors too, like the arrival of a new sibling, moving houses, starting daycare, etc. Sleep can also get worse with minor illnesses when babies cannot sleep well because they are in discomfort due to the illness.

Whatever causes sleep regressions, these issues should resolve, and sleep should go back to normal in a few weeks. However, during these times, babies can develop new habits that parents can inadvertently reinforce, and these habits can persist for months, even after the original cause ceased to exist. Imagine a baby who is already night weaned and sleeps through the night, but now starts waking up several times per night due to teething pain. His parents want to help him and give him a bottle with some warm milk to ease the pain. This baby might cry for milk at night even after the teething is over, simply because he got used to it. The general advice about sleep regressions is to try to avoid forming new, undesirable, long-term habits for a short-term phase.

Is the 4, 6 or 12 month sleep regression real?

You might have noticed that I didn't really write about the different sleep regressions in more detail in terms of what causes them or what to do with them. And that is because sleep regressions are probably not real. What did I say? What I mean is sleep regressions obviously happen, but by sleep regression, I only mean when sleep gets worse for short period of time. That is a sleep regression by definition.

It obviously happens to many babies, but I don't think that sleep regressions at specific times — like the 4-month sleep regression, the 6-month sleep regression, the 8-month sleep regression, or the 12-month sleep regression — I don't think that these are "real".

What does this mean? All the things that I have mentioned that could cause sleep regression can happen at variable times for babies. For example, developmental milestones, like nap transitions, crawling, walking, teething, et cetera. And it's pretty normal to happen two, three months earlier or later than the average.

For example, babies on average learn to walk around 12 months of age, but it is absolutely normal for a baby to learn to walk at nine months of age or even 15 months of age or even later. So if learning to walk causes a sleep regression, then would you say that this is the 12-month sleep regression? That it should cause a sleep regression at 12 months of age?

So you see that the time range when babies learn to walk is more than half a year. How could this cause sleep regression at a certain age? And if you think about outside factors like starting daycare, moving houses, the birth of a sibling, et cetera, it's even more the case. These are completely random things in the life of a baby. So it's just normal that they would cause sleep regressions at different times.

What does the research show?

In fact, if you search the scientific literature for the 2-month sleep regression, or the 4-month regression, the 6-month sleep regression, or the 12-month sleep regression, you don't find anything. The scientific literature doesn't talk about this. And if you look at the scientific literature for the development of sleep, where researchers look at babies at different ages, or where researchers follow babies in a longitudinal study, where they follow babies from birth to, let's say, one year of age and they record how much they sleep and how they sleep, then if sleep regressions at a specific time were real, you would expect some kind of change at certain time points, right?

So what would be the sign of a sleep regression? Like less sleep, more night wakings, more night feedings, difficulty falling asleep, more time staying awake at night or shorter naps. So this means that if you plotted the number of night wakings from birth to 12 months of age for 100 babies, if the 6-month sleep regression was real, then there would be a kind of bump in the number of night wakings around six months of age, right? Or in the number of night feedings, or there would be a bump in the average time babies stay awake at night.

So we wouldn't see a straight line as the babies develop, but there would be some kind of change around certain times. I looked at several scientific papers and I didn't see any changes. So there isn't a consistent change in sleep quality where general wisdom says there's a sleep regression. Maybe I have seen something around nine months of age, but I didn't analyze it statistically. I don't have the data. In some studies, I have seen some kind of decrease in sleep quality around nine months of age, but I wouldn't swear on it.

This is why I say that the 6-month sleep regression or the 12-month sleep regression, or the 4-month sleep regression doesn't exist. But it doesn't mean that sleep regressions do not exist. I just believe that they don't really happen at a certain time since everything that causes sleep regressions is so variable that it would be very difficult to pinpoint an age when it happens.

But if you think about an analogy, for example, getting a cold; babies get a cold all the time. It happens at different times for very different reasons, but there is no such thing as the 4-month health regression or the 6-month health regression, et cetera. It happens to every child at different times, and there's no particular month that stands out when suddenly more children catch a cold. But just because it doesn't show in the average data, it doesn't mean that it doesn't happen.

What causes a sleep regression?

What parents usually would like to know about sleep regressions is what's causing them. The idea is that if you know the cause, that it would be easier to treat them. But since, as we have seen, all the things that cause sleep regressions can happen in quite a large time range, it would be very difficult to say what causes sleep regressions.

Most of the time, there are several factors that contribute to a baby's sleep getting worse. I think when you look at the sleep regression, there are several factors that can be at play and you can look at your own child and see which ones could be a factor in his or her case.

Developmental milestones

At six months of age, there are several developmental milestones that could contribute to a sleep regression. For example, learning to roll over, creeping and crawling, learning to sit up and babbling. These are all developmental milestones that could happen at this age. Usually, babies are so fascinated with their new skills that they just can't stop practicing them. They are just too wired up to settle down and to go to sleep. So these can cause sleep regressions. What can you do about them? Nothing. You just wait it out, wait until the baby learns these new skills, and that's it.

More social, so harder to wind down

Around six months of age, babies get a bit more social. This means that they are more interested in interacting with other people, their parents especially. That means that they might need more time to wind down after a social interaction. Maybe the baby was outside in the living room with the parents and maybe his or her siblings. Maybe two months earlier, the baby only needed to be brought into the nursery and he would settle down in a few minutes. But maybe now the baby needs more time, like half an hour in a quiet and dark place to settle down after these very interesting things that happened to her.

Starting solids

Another thing that usually happens around this time is that babies start to eat solids. And certain foods can be hard to digest and can cause stomach aches or wind or diarrhea or rashes. So all these things can contribute to discomfort that will not allow babies to go to sleep. If the sleep regression is caused by some of the foods that the baby usually eats for dinner, then figuring this out would be very difficult. But once you know the culprit, then you just eliminate that food at dinner time and that will be it.

Another thing that's also developmental is that some babies start to sleep lighter when in motion. So as a newborn, maybe your baby liked to sleep in the pram, but now it prevents the most restorative deep sleep from happening. So your baby will sleep lighter when in motion. And that might mean that if you are on the go during the naps, it might ruin your baby's sleep, and that, in turn, will affect nighttime sleep, too.

Object permanence and separation anxiety

Babies also go through cognitive changes, namely, object permanence develops and separation anxiety. So now your baby knows that you exist, even when you are not there, and they are afraid of being separated from you. So, of course, they will not want to fall asleep independently or alone. They will not want to be alone in a room at all. This is also a thing that you cannot really do much about. You just wait until the babies get used to this, but what you can do to get this process a bit faster is to play peekaboo with the baby because that's a practice of object permanence, right?

And, of course, the last thing is teething or tooth eruption. Well, you can blame teething for anything at any time because it's almost continuous. Of course, teething pain can cause sleep regressions.

So we went through several possible reasons that could cause sleep regressions around six months of age. Also, I mentioned how you might deal with these factors. But my general advice is not to get hung up on figuring out the specific reasons why your baby is having a sleep regression, except if it's a very obvious one, like food intolerance or something like that. Usually, it is really difficult to figure out what causes sleep regression. And anyway, most of the time, it doesn't cause any difference in how to deal with it.

Frequently asked questions

Is the 6 month sleep regression real?

Sleep regressions are real; the numbered ones are not. Every cause of a regression, from nap transitions to crawling, teething and daycare, happens across a wide range of ages, and the longitudinal sleep studies show no bump in night wakings at any particular month.

What causes sleep regressions at 6 months?

Several things at once, usually: new motor skills the baby wants to practise, becoming more social and needing longer to wind down, starting solids and the digestive discomfort that can bring, sleeping lighter in motion, object permanence and separation anxiety, and teething.

How long does a sleep regression last?

A few weeks, and then sleep goes back to normal on its own. The risk is not the regression itself but the habits formed during it: a bottle offered for teething pain can outlast the teething by months.

What should I do during a sleep regression?

Mostly wait it out, and avoid solving a short-term phase with a long-term habit. If the cause is obvious, such as a food that does not agree with your baby, deal with that. Otherwise do not spend your energy trying to identify which regression it is.

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