Four month sleep regression

How to survive the 4 month sleep regression

You may have had an amazing sleeping newborn, but now that they are 4 months old, they've suddenly started waking a lot more in the night and catnapping in the day. You're exhausted and wondering what on earth has happened to your baby?!

This is the 'famous' 4 month sleep regression and it's actually the biggest change in your baby’s sleep that will ever happen. So what's it all about and what can you do to get through it? Read on to find out!

In this article:

  • What is a sleep regression?
  • What causes the 4 month sleep regression?
  • How long does this regression last?
  • Tips for self-settling
  • Is it the 4 month regression or something else?
  • How to survive the 4 month sleep regression

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What is a sleep regression?

A sleep regression is a period when a baby or toddler who has been sleeping well suddenly starts waking at night, being difficult to settle and/or skipping naps. This is a natural and normal change for your baby, but it can be a distressing time for parents.

Your baby will go through a number of sleep regressions in the first 2 years of their life, the biggest being the 4-month sleep regression. You can learn more about these sleep regressions HERE.

A key part of moving through these sleep regressions successfully is understanding what causes them, and what’s happening with your baby at this time.

What causes the 4 month sleep regression?

Around 4 months of age, your little one’s sleep starts to operate more like ours as adults, where we go in and out of deep sleep and light/REM sleep. REM sleep is a lighter sleep where we are more likely to wake up if something is bothering us... and it's the same for babies at this age!

Rather than being a regression, we actually prefer think of this stage as a progression and maturation of your baby’s neurological development. Here are the key changes that happen to your baby's sleep at this time:

  • Day time sleep cycles shorten to be around 35 to 45 minutes long.
  • Night time sleep cycles shorten to be around 2 hours long.
  • Your baby will now start to fully rouse between each sleep cycle, rather than drift between cycles automatically as they did when they were younger.

The result of this neurological change is that your baby can start catnapping during the day and waking more overnight. This change also marks the point in which learning to self-settle can really benefit your baby’s napping and night-time sleep.

Sleep has now become a very conscious thing for your little one. If they have certain sleep associations such as being rocked, fed or patted to sleep, they will need you to repeat this action every single time they wake between cycles… That’s right, EVERY SINGLE TIME. That’s every 35 to 45 minutes during their naps and every 2 hours overnight.

NOTE: Remember not all babies will reach these developmental stages at these exact ages, so if your baby is 3.5 months and starts waking every 2 hours overnight, it's safe to assume they've hit the 4 month regression.

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How long does this regression last?

Now, we hate to break it to you but the 4 month sleep regression is a permanent change to how your baby sleeps and won’t go away until they have learnt to self-settle.

Self-settling is simply your little one's ability to fall asleep without your help. It is definitely something that babies this age are capable of doing, if everything is lined up right for them, such as their awake times, nap structure and they have a good predictable pattern to their day.

During the 4 month sleep regression, sleep associations start to play a big part in your baby's ability to go to sleep and stay asleep because sleep has now become an active process rather than a reactive process (like when your baby was younger).

From this age onwards, the way babies are put to sleep at the start of a nap or at bedtime is the method they completely rely on to go to sleep. When your baby then naturally wakes at the end of a sleep cycle, if that same sleep association isn’t there they will not be able to go back to sleep without it.

This is why your baby may start napping for only 45 minutes during the day and waking every 2 hours at night and need your help to go back to sleep. You must remove your assistance in the sleep equation to give your baby the chance to put their new sleep powers to the test.

Like learning to read, self-settling is a skill that doesn't simply develop overnight. It is something completely new for babies and they need a process of coaching, consistency and the chance to learn to do it themselves. By giving in and continuing to settle our baby at the first grizzle, we’re denying them the chance to work on this new skill and not doing them any favours in the long run.

Here are the most important things to remember when it comes to self-settling:

  • Babies under 3 months aren't capable of conscious self-settling - the best you can do is to encourage good sleep habits at this age. If everything is lined up, some younger babies may instinctively self-settle to sleep.
  • From 4 months you can gently begin to guide your baby to self-settling, as this is when it becomes a learned skill rather than an instinctive behaviour. Our Little Ones App contains several gentle self-settling methods to choose from that are tailored to your baby's age and current sleep association.
  • You might experience a bit of protesting as your little one gets used to this new way of going to sleep, particularly if you have an older baby or toddler.
  • A baby who is over or under tired will find it really hard to self-settle. Our Little Ones App can help with this by making sure your baby is perfectly ready for sleep, which gives them the best chance at self-settling.
  • Consistency is absolutely key - don't give your baby mixed messages by encouraging them to self-settle some of the time, then settling them all the way to sleep at other times.
  • A dark room, white noise and a swaddle (for babies under 5 months who aren't rolling yet) or baby sleeping bag are positive sleep associations that can greatly help your baby learn to self-settle.
  • A hungry baby won't settle no matter what you do, so make sure your little one is well-fed and burped before putting them down for sleep.
  • Have high expectations of your little one and work hard to achieve them. They CAN do it - and so can you!

Do sleep regressions ‘ruin’ the sleep training you have already done or plan to do?

The answer is not at all! Now, just to clarify, by "sleep training" we mean establishing a consistent nap routine for your baby and guiding them towards the skill of self-settling when they are ready.

Establishing a consistent routine and positive sleep habits early on is well worth the effort because it will help you down the line. You'll be able to quickly identify when something like a sleep regression is occurring because you will easily recognise the changes in your baby’s sleeping habits.

Certainly, during a regression it makes it a little more tricky to follow a routine or schedule, but making sure your baby's awake windows and nap lengths are spot on for their age does help a lot when it comes to self-settling. And since self-settling is the only way through the big 4 month sleep regression, we would say the more you’re prepared and consistent you are, the better!

Is it the 4 month sleep regression or something else?

The main sign that your little one is going through a regression is that their sleeping pattern dramatically changes. They’ve suddenly gone from sleeping well to not being able to settle for naps and bedtime, or catnapping during the day, or waking more overnight.

But there are other factors that can cause this kind of sudden change in your baby's sleep too, including:

Over or under tiredness

Your baby may have simply outgrown their current nap pattern. Small tweaks to their awake windows or nap lengths may be all that's needed to get their sleep back on track again!


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Between 4-6 months babies are getting ready to start solids and their milk feeds don't sustain them for as long anymore. This means they can start to wake for an extra feed overnight now, even if they were previously sleeping through without a feed.

NOTE: Waking for one extra feed at night is NOT the same as waking and feeding every 2 hours. If your baby is waking every 2 hours and just having a small feed each time, it's more likely that they are relying on feeding/sucking to get back to sleep in between sleep cycles, rather than waking genuinely hungry.


For the most part, teething is really only uncomfortable for your baby for a day or so right as the tooth is breaking through the surface of the gum - which you’ll definitely be able to see! If your baby's sleep has been disrupted for more than a week, it's not due to teething.


A sudden change in your baby's sleep or settling can sometimes be an early sign of illness. THIS article shares some other signs to look out for but if you are at all concerned about your baby's health, please see your health practitioner.

If you can rule these factors out and your baby is catnapping during the day and waking every 2 hours at night (usually from midnight onwards), chances are you have hit the 4 month sleep regression.


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How to survive the 4 month sleep regression

Although the 4 month sleep regression won’t go away until your little one has learnt to self-settle, there are a few ways to deal with this regression in the meantime:

  • First, recognise what is causing your baby to wake up. If it is a sleep association such as being rocked or patted to sleep, create a plan to wean your little one from that sleep association and guide them towards self-settling.
  • When your little one wakes, give them a chance to self-settle back to sleep. Rushing in and assisting them straight away is not giving them the chance to practice this new skill!
  • Your baby’s room environment plays a huge role in how they sleep. The darker their room, the better - especially at this age as they’re very sensitive and responsive to light. We also suggest playing continuous white noise to help your baby transition from light sleep to deep sleep without fully waking up.
  • Stick to your routine - consistency is key! Although the 4 month sleep regression might make this difficult, try your best to stick with it. Make sure your baby's routine (naps and awake times) are age appropriate with the help of the sleep schedules in our Little Ones App.
  • Create a consistent bedtime routine so that your baby learns to accept sleep as the final component of the routine. Find out more about the importance of a bedtime routine HERE.
  • Foster positive sleep habits BEFORE the regression kicks in. Over time, gradually reduce the amount of active settling that you do. Try putting your baby into bed drowsy, then give them a chance to do the last bit of falling asleep on their own. Aim for your baby to do at least one nap per day in their bed.

The 4 month sleep regression is tough, there are no two ways about it! It is a rough couple of months as your baby adjusts to the massive changes happening in their brain. Luckily, there are ways through this tricky phase and ways to minimise the sleep impact on your baby and your whole family. The best place to start is with our award-winning Sleep Programs.

"I have been following your program now for three weeks and the difference in my little boy who is 5 months old is amazing, we have a structured day with a morning nap and afternoon nap both in his cot and a bedtime of 7pm. And this week he has started to sleep through the night. I feel more relaxed and have time to catch up on things that before I couldn't do as he just catnapped for 20 minutes at a time. Thank you so much you saved my sanity. Xxx" - Vicky




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