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The Four-Month Regression

As a professional sleep consultant, I hear the term “regression” used in regards to just about every imaginable circumstance. Essentially, if the baby doesn’t sleep well for a couple of nights, parents start dropping the “R” word. Some people subscribe to the idea that there’s an eight-month regression, a nine-month regression, a one-year regression, as well as teething regressions, growth spurt regressions, and so on. Others see these as simple hiccups caused by extenuating circumstances.

The only exception is the four-month regression, which everybody agrees on and for good reason. It’s the real deal, and it’s permanent.

In order to understand what’s happening to your baby during this stage, first you need to know a few things about sleep in general. Here’s the science-y part, told in plain English.

Many of us just think of sleep as an on-or-off situation. You’re either asleep or you’re not. But sleep actually has a number of different stages, and they make up the “sleep cycle,” which we go through several times a night.

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

Stage 2, which is considered the first “true sleep” stage, is where people tend to realize, once they’ve 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’re going to wake up groggily.

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

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

Once we’ve 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 dreaded regression we were talking about originally?

Well, newborn babies only have two stages of sleep: stage 3 and REM, and they spend about half their sleep in each stage. But around month 3 or 4, there is a reorganization of sleep, as they embrace the four-stage method of sleep that they’ll continue to follow for the rest of their lives.

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

That’s not to say that we want to prevent or avoid the 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, however, we’re able to identify certain comforting truths the baby might not be privy to. When we wake in the night, we’re able to recognize that feeling: “Hey, I’m here in my bed, it’s still nighttime, my alarm isn’t going to go off for another three hours, and I’m reasonably certain that there are no monsters lurking under my bed. I can go back to sleep.”

And we do. Usually so quickly that, the next morning, we don’t even remember the brief encounter with consciousness.

A four-month-old baby, of course, doesn’t have these critical thinking skills. To a four-month-old baby who fell asleep by her mother’s breast, the reasoning could look more like “OK, last thing I remember, there was a familiar, beloved face, I was having dinner, and someone was singing me a soothing song about the Teddy Bears’ Picnic. Now I’m alone in this dark room, there’s no food, and there’s probably at least three, possibly four, scary monsters close by.”

That’s probably an exaggeration, but who knows what goes on in the mind of a four-month-old baby?

Anyways, now that the baby suddenly realized that their Momma’s not around, and they’re not entirely sure where they’ve gone, the natural response is freaking out a little. That stimulates the fight-or-flight response and, next thing you know, the baby’s not going back to sleep without a significant amount of reassurance that everything is OK.

The other major contributor to this four-month fiasco is that up to this point, parents have either been putting their baby to sleep with a pacifier, or by rocking them, or by breastfeeding them, or some similar technique where the baby is helped along to fall asleep.

Now that the baby’s spending more time in light sleep, and therefore has a higher probability of waking up, this suddenly becomes a much bigger issue. These sleep props or sleep associations can be very sneaky indeed, because although they may be helpful in getting your little one to that initial nodding off stage, the lack of them when they wake up means that the baby’s not able to get back to sleep again without some outside help. Cue the fight-or-flight, the crying, and the adrenaline. When this starts happening every half an hour, parents can find themselves in a nightmarish situation.

The good news for anyone experiencing the dreaded 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’s actually the opposite of what your baby is experiencing. This would be much more aptly titled the “Four-Month Sleep Progression” if we wanted to get literal. It is, as some would say, “a natural part of growing up.”

So, here’s the big question: what can you do to help your little one adjusts?

First off, get all the light out of your baby’s room. I’m not kidding around here. You might think your baby’s room is dark enough, or that your 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.


The baby’s room should be dark. I mean coal mine on a moonless night kind of dark. Tape garbage bags over the windows if you have to, or cover them with tinfoil. It won’t be pretty, but it’ll be effective.

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 for naps and bedtime.

The other nemesis of daytime sleep (and nighttime for that matter, although not nearly as often) is noise. Whether its UPS ringing the doorbell, the dog warning you that the squirrels are back and for sure going to attack the house this time, or something falling on the floor three rooms away. With the baby spending more time in lighter sleep, noises will startle them easily and wake them up, so a white noise machine is a great addition to your nursery.

“Wait, isn’t that a prop?” you might be asking. Well, in a way, it is, but it doesn’t require any winding, resetting, reinserting, or parental presence. It’s just there and it can be on as long as the baby’s sleeping, so it’s not a prop we need to avoid.

Bedtime routines are also an essential component to getting your baby sleeping well. Try to keep the routine around four to five steps, and don’t end it with a feed. Otherwise, there’s a risk your baby will be nodding off at the breast or the bottle, and that will create the dreaded “association” that we talked about earlier.

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, and your baby should go into their crib while they’re still awake.

If you’re noticing your baby’s 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, if your baby does wake up, and chances are, they probably will, give them about ten minutes before you go in. I know this can be hard when they’re crying, but give them an opportunity to figure out the “get-back-to-sleep” process for themselves. If they’re still fussing after ten minutes, go in and offer a feed, but remember! Don’t feed to sleep! Keep the baby awake through that feed, whatever it takes.

Now, there are going to be regressions, actual regressions, later on in your little one’s youth. Travelling, 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 pacifiers, 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 your baby 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 best time. I offer a free 15-minute evaluation so I can get to know the specifics about your little one’s situation. Book your call now and we can move forward as soon as you’re ready to get your little one sleeping through the night!

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