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The Four Month Sleep Regression

As a Sleep Consultant, I hear the term ‘regression’ thrown around all of the time. Almost any time a baby is not sleeping well for a few nights parents tend to start dropping the ‘R’ word. Some people subscribe to the idea that there’s an 8 month regression, a 10 month regression, a 12 month regression – as well as teething regressions, and growth spurt regressions, and so on. Others view these as simple hiccups caused by extenuating circumstances.

The Four Month Sleep Regression, however, everybody agrees on – and for good reason. It’s the real deal, and it’s permanent.

In order to understand what is happening for your baby during this period, you first need to know a few things about sleep in general.

Many of us just think of sleep as an on/off situation. You’re either asleep or you’re not. In actual fact, sleep involves a number of different stages which make up what we call ‘sleep cycle’s. We move through these ‘sleep cycles’ over and over while we sleep at night.

Here's a summary of each of the different stages within each cycle:

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

STAGE TWO is considered the first ‘true’ sleep stage. This is where people tend to realise once woken up, that they actually were sleeping. For anyone taking a ‘power nap’, this is as deep as you want to go otherwise you will wake up feeling groggy.

STAGE THREE is deep and regenerative. It is also known as ‘slow wave’ sleep. This is where the body starts repairing and rejuvenating the immune system, muscle tissue, and energy stores. It also facilitates growth and development.

STAGE FOUR is Rapid Eye Movement (REM) sleep. This is where the brain starts to kick in and consolidate information and memories from the day before. This is also the stage where dreams occur.

Once we’ve gone through all of these stages, we have completed one sleep cycle. At the end of each sleep cycle we come to the ‘surface’ of sleep (almost awake but not quite) before we then link into another sleep cycle. We continue this process throughout the night until our alarm goes off or we wake naturally in the morning.

So, what does this have to do with the dreaded four month regression we were talking about originally?

Well, newborn babies only have two stages of sleep within their sleep cycles: stage three ‘deep sleep’, and REM sleep. They spend about 50% of the time between each of the two stages. Around the third or fourth month, however, there is a reorganisation of a baby’s sleep where they then adopt the four stage sleep cycle structure that they will continue to follow for the rest of their life. So it’s not so much a regression, after all, but a transition.

When this reorganisation takes place, a baby transitions from 50% REM sleep to 25%, with 25% of sleep now being spent in the first two stages discussed above. A key change here is that the first two stages of sleep are much lighter compared to REM sleep. With more time spent in lighter stages of sleep, a baby is much more susceptible to night wakings.

The night wakings themselves are not our core problem, though. In fact, wakings are natural and even as adults we experience wakings throughout the night.

As adults, however, we are able to identify certain comforting truths that a baby may not. We are able to recognise that “Hey, I’m here in my bed. It’s still night time, my alarm doesn’t go off for another 3 hours, and I’m reasonably certain there are monsters lurking under my bed … so I’m going back to sleep”. So we do. Usually so quickly that the next morning we don’t even remember this brief encounter of consciousness.

A four month old baby, of course, lacks these critical thinking skills. To a baby who has fallen asleep at the breast, or held in your arms and rocked to sleep, their reasoning could go more to the tune of “Ok, last thing I remember is a familiar loving face, feeling warm and snug, and hearing a lullaby. Now I’m alone in this dark room, there’s nothing to snuggle into, and there’s probably a big monster in the cupboard over there”.

That’s probably a bit of an exaggeration, but you get the picture. Essentially, baby suddenly realises that Mum or Dad is not around, they’re not entirely sure where you’ve gone, and they don’t know when you’re coming back – the natural response is to freak out a little. This stimulates the fight or flight response and, next thing you know baby’s not going back to sleep without a significant amount of reassurance that everything is ok.

So our core problem here, is that baby is not familiar with getting to sleep independently (many families get into a pattern of rocking, feeding, patting, or even bouncing their baby to sleep). This is unlikely to be an issue for a newborn as they transition back and forth between REM sleep and deep sleep easily throughout the night, rarely waking unless hungry. However, once lighter stages of sleep are added in and they are more likely to wake throughout the night, baby then begins to need more and more support throughout the night to get back to sleep.

When this starts to happen every half hour to an hour all night, parents can find themselves in a nightmarish situation.

So, onto the big question. What can you do to help your little one adjust?

First of all, get all of that light out of your baby’s room. I’m not joking around here. Your baby’s room should be coal mine on a moonless night kind of dark. Tape garbage bags over the window if you have to, or cover them with alfoil.

Babies 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 the nursery absolutely pitch black during naps and bedtime.

The other nemesis of daytime sleep (and nighttime for that matter, just not nearly as often) is noise. Whether it’s the mailman at the door, the dog barking at birds in the yard, or something falling on the floor three rooms away. With your baby spending more time in lighter sleep, noises will startle them easily and wake them up. This is why white noise machines are commonly recommended for use as a sleep aid.

Bedtime routines are also an essential component to getting your baby to sleep well. Try to keep the routine to about 4 – 5 steps, and don’t end it with a feed. Ending a routine with a feed means running the risk of baby nodding off at the breast or bottle – only to wake later startled when it is no longer there. The whole bedtime process should be about 20 – 30 minutes long and your baby should go down into the cot awake. If you’re noticing that your baby is getting fussy before bedtime, you’ve probably waited too long. Four month old babies should really only be going about 2 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 life. Travelling, illness, teething – all of these can cause your little one to have a few bad nights in a row. But when it comes to the Four Month Sleep Regression, I am 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 structure that they will be following for the rest of their life. Four glorious stages repeated multiple times a night.

By taking this opportunity to teach your baby the skills they need to self-soothe and link those sleep cycles together independently you will be giving them a gift they will enjoy for the rest of their lives!

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