4 Month Sleep Regression

As a certified sleep consultant, I hear people talk about “regression” all the time regards to anything and everything that isn’t quite going smoothly. If baby does not sleep well for a few of nights, parents start calling it a regression. Some people have heard that there is an eight month regression, a 9 month regression, a 1 year regression, as well as teething regressions, growth spurt regressions, and so on.

So to understand what is happening to your baby during these stage’s, first you need to know a little bit about sleep in general. So here is the biological part, around sleep.

Many of us just think of sleep as you either are or you are not. But sleep actually has a 4 different stages, and they make up the “sleep cycle,” which we go through several times a night.

Stage 1 is the first stage we are all familiar with where you can just feel yourself drifting off, but don’t really feel like you have fallen asleep. Anyone who has ever seen their partner nodding off in front of the TV, told them to go to bed, and received the response of, “I wasn’t sleeping!” knows exactly what this looks like.

Stage 2, which is considered the first “true sleep” stage. This is where people tend to realize, once woken up, that they actually were sleeping. For anyone taking a “power nap,” this is as deep as you want to go, or else you are going to wake up groggy.

Stage 3 is deep and regenerative. Also known as “slow wave” sleep, this is where the body starts repairing and rejuvenating the immune system, muscles tissue, energy stores, and sparks growth and development.

Stage 4 is REM (rapid eye movement) sleep. This is where the brain starts to fire and consolidates information and memories from the day before. It is also the stage where we do most of our dreaming.

Once we have gone through all of the stages, we either wake up or come close to waking up, and then start over again until the alarm goes off.

So what does this have to do with the painful regression we were talking about?

Well, newborn babies only have 2 stages of sleep; stage 3 and REM, and they spend about half their sleep in each stage. But at around the third or fourth month, there is a reorganization of sleep, as they embrace the 4-stage method of sleep that is adult like and they will continue to follow for the rest of their lives.

When this change takes place, baby moves from 50% REM sleep to 25% in order to make room for those first two stages. So although REM sleep is light, it’s not as light as these 2 new stages that they are getting used to, and with more time spent in lighter sleep, there is more of a chance that baby is going to wake up.

That is not to say that we want to prevent or avoid baby waking up. Waking up is absolutely natural, and we continue to wake up three, four, five times a night into adulthood and even more in old age.

As adults, we are able to identify certain comforting truths. When we wake in the night and are able to recognize that, “ I’m here in my bed, it is still nighttime, my blanket has fallen off and I feel cold, so I will pull my blanket up and go back to sleep. Babies haven’t quite mastered this understanding.

A four month old baby, does not have enough critical thinking skills. To a four month old baby who fell asleep at her mother’s breast, their simple thought process could be, “OK, last thing I remember, I was being held by my warm, comfy mum, I was having dinner. Now I’m alone in this dark room, there’s no food, and where is my mum?

Now that baby has suddenly realized that Mummy is not around, and they are not sure where they have gone, the natural response is start crying. That stimulates the fight-or-flight response and, next thing you know, baby is not going back to sleep without a significant amount of reassurance that everything is OK.

The other major factor to this 4 month regression, is that up until now, parents have either been putting their baby to sleep with a dummy, or by rocking them, or by breastfeeding them.

Now that baby is spending more time in light sleep, and therefore is more likely to be waking up, this then creates a major issue. These sleep props can be very cheeky, although they may have been helpful in getting your little one to that initial nodding off stage, the lack of them when they wake up means that baby is not able to get back to sleep again without some outside help.

So, the good news for anyone who is currently suffering through the Four Month Sleep Regression is that it’s not, in fact, a regression at all. A regression is defined as “reversion to an earlier mental or behavioural level,” and that is actually the opposite of what your baby is experiencing. This would be much more aptly titled the “Four Month Sleep Progression”

So, onto the big question. What can you do to help bub get through this stage?

First off, make baby’s room SUPER dark. You might think that baby’s room is dark enough, or that baby might not like the dark, and that it’s comforting to have a little bit of light coming through the windows or seeping in from the hallway.


Baby’s room should be dark. I mean dark as a cave on a moonless night kind of dark. Cover them with alfoil.

Newborns and infants are not afraid of the dark. They are, however, responsive to light. Light tells their brains that it’s time for activity and alertness, and the brain secretes hormones accordingly, so we want to keep that nursery absolutely pitch black during naps and bedtime.

The other enemy of daytime sleep, is noise. Whether its someone ringing the doorbell, the dog barking. With baby spending more time in lighter sleep, noises will startle them easily and wake them up, so a white noise machine or fan is a great addition to your nursery.

Bedtime routines are also essential to getting your baby sleeping well. Try to keep the routine to about 4 or 5 steps, and don’t end it with a feed. Otherwise, you risk baby nodding off at the breast or the bottle, and that will create the “association” that we talked about earlier.

So try to keep the feed near the beginning of the routine and plan the songs, stories, and getting into PJs towards the end. The whole process should be about 20 – 30 minutes long, and baby should go into their cot while they’re still awake.

If you’re noticing baby getting fussy before bedtime, you’ve probably waited too long. Four month old babies should really only be going about two hours between snoozes, and bedtime should be between 7 and 8 at night.

Now, there are going to be regressions, actual regressions, later on in your little one’s youth. Traveling, illness, cutting teeth, all of these things can cause your little one to have a few bad nights in a row. But when it comes to the four month “progression,” I’m happy to report that this is a one-time thing. Once you’re through this, your baby will have officially moved into the sleep cycle that they’ll essentially be following for the rest of their life. Four glorious stages repeated multiple times a night.

And by taking this opportunity to teach them the skills they need to string those sleep cycles together, independently, prop-free, without any need for nursing, rocking, or dummies, you’ll have given them a gift that they’ll enjoy for the rest of their young lives.

Of course, some kids are going to take to this process like a fish to water, and some are going to be a little more resistant. If yours falls into the former category, count yourself as lucky, take delight in your success, and go ahead and gloat about it on Facebook.

For those of you in the latter camp, I’m happy to help in any way I can. Just visit my website or give me a call and we can work on a more personalized program for your little one. The most common thing I hear after working with clients is, “I can’t believe I waited so long to get some help!” So if you’re considering hiring a consultant, now is absolutely the time. I offer a free 15 minute evaluation so I can get to know the specifics about your little one’s situation, so book a call now and we can move forward as soon as you’re ready to get your little one sleeping through the night!