Your ultimate guide to the 4-month sleep regression: Including 5 tips on how to survive it

Updated: Jul 7, 2021

You finally got into a good routine with your baby and they just started sleeping longer stretches at night and is napping pretty well during the day, when suddenly nights start falling apart and your little one is again up every 2-3 hours overnight and starts catnapping during the day. If this sounds like your baby, then you are most likely going through the 4 month sleep regression.

What you need to know about the 4 month sleep regression

The 4 month sleep ‘regression’ is actually more of a progression as this is the time when your baby’s sleep cycles mature but in terms of their quality of sleep it can be called a regression. This is the time when your baby’s sleep matures and sleep cycles start to develop.

This is a permanent change and not something your little one will ‘outgrow’. The development of these sleep cycles usually happens between 8-16 weeks of age so it does not happen at exactly 4 months for every baby. A typical sleep cycle during the day looks as follows:

0-10 min: Falling asleep

10-20 min: Falling into deep sleep

20-30min: In deep sleep (difficult to wake here)

30-40min: Coming out of deep sleep

45-50min: Light sleep (easy to wake here)

When your little one was a newborn they were experiencing two different sleep cycles only but as your baby gets older your baby starts to develop more sleep cycles and will cycle through 4 stages of sleep at night, just like adults. This means that your baby will now spend more time in lighter sleep, meaning wake-ups are more frequent.

To further understand this change let’s go back in time a little. When your baby was first born, they were quite sleepy as they were born with lots of melatonin (sleep hormone) passed through the placenta from mum. This means in the newborn stage, you can most likely get away with feeding your baby, swaddling them and putting them down to sleep easily as your baby would immediately enter deep NON-REM sleep (rapid eye movement or dream sleep). After about 3 weeks melatonin starts to wear off and your little one starts to wake up more. Your newborn does not start to produce their own melatonin for a few weeks or months to come so putting them to sleep now becomes harder. At the same time your little one’s sleep cycles are starting to emerge and their circadian rhythm is starting to mature.

This is why your baby might start waking up after 45 minutes during the day whereas they used to nap for 1-2 hours. Please know this change is completely normal and does not mean that your baby’s sleep is broken.

Not every baby goes through this ‘regression’

The reason why the 4 month sleep ‘regression’ does not affect all babies is that babies who have already learned to self-settle will simply put themselves back to sleep after the completion of one sleep cycle. Babies that have been following a consistent routine from early on are also less likely to have disrupted sleep as the habit to sleep has already formed. Further babies that usually nap in a carrier or on you, are assisted back to sleep quickly and easily, so the regression is not as noticeable.

Not only can the 4 month sleep regression start before 4 months it can present as late as 6 months as your baby’s sleep might only get disrupted once complete overtiredness sets in, due to weeks of short day time naps. This then usually results in overtiredness at bedtime which leads to frequent night wakings.

Every baby goes through this maturation of sleep cycles but not every baby’s sleep will worsen as a result. Babies that are rocked, bounced or fed to sleep are more likely to go through a sleep ‘regression’ as they have not yet learned how to self-soothe. So what does the 4 month sleep regression look like?

The changes happening during the 4 month sleep regression

Your baby’s 45 minute sleep cycle will become quite apparent. Your baby will finish one sleep cycle, wake up and cry out for help to get back to sleep if they were fully assisted to sleep. This is why catnapping can emerge. So instead of peacefully drifting from one sleep cycle to the next, your baby will wake up and look for their sleep association (rocked, fed, bounced etc.) instead of going back to sleep.

At night your baby’s cycles will change from a full 4 - 6 hours to a partial 2 - 4 hours so you will notice more frequent night wakings and more difficulty settling your little one back to sleep as they are once again looking for their sleep association and wake up fully if it is no longer present.

These partial arousals are normal and protective in nature as your baby will wake up to make sure everything is ok and would normally settle back to sleep, provided the sleep environment hasn’t changed. This is why a baby that is rocked or fed to sleep and then placed in their bassinet/cot is more likely to wake up fully during a partial arousal as the sleep environment has changed and your baby is looking for the same conditions that were there when they fell asleep.

Signs your baby is going through the 4 month sleep regression

  • Catnapping (45 minute naps)

  • Waking up at the 30 minute mark crying (overtired)

  • Frequent night wake ups (as often as every 2 hours)

  • More difficulty to settle baby back to sleep after a night waking

  • Nap routine falling apart

How to manage the 4 month sleep regression

Your response will most likely be to feed or rock your baby back to sleep at every night waking and get them up after every short nap. So your baby will continue to wake up every 2 hours as they are unable to go back to sleep by themselves.

These wake ups will not resolve themselves as the 4 month sleep regression is a permanent change. So your baby will take in more and more calories at night and the night wakings will continue due to habit and genuine hunger. This is also due to the fact that around this age your baby becomes more aware of their surroundings and will be a more distracted feeder during the day and take in fewer calories as a result. Your baby is now reverse cycling (feeding less during the day and more at night), a habit which can be difficult to fix.

Work on daytime sleep before the regression hits

If your baby has not yet hit the 4 month sleep regression but is catnapping during the day, it is best to work on re-settling with your baby. What does this mean? This means that if your baby wakes up after 30 or 45 minutes, re-settle them for at least 40 minutes before getting them up for a feed. This teaches your baby that only completing one sleep cycle is not enough and your baby will get into the habit of taking longer naps.

This also means that your baby is not getting progressively more overtired and will more likely continue to sleep well during the night even once the 4 month sleep ‘progression’ hits.

When your baby is already in the midst of the regression

Since the 4 month sleep regression is not a regression but a progression, your baby will not simply outgrow this change. As previously mentioned, this progression is a permanent change and with some help from you, your baby’s sleep can and will improve.

1 ) Look at your baby’s sleep environment

Ensure your baby’s sleep space is nice and dark to promote the production of melatonin. A dark sleep space will also avoid your baby getting distracted when waking up too early from a nap.

2) Use the right sleep props

Not all sleep props are bad and introducing some independent based sleep props such as white noise, swaddles, and sleeping bags is a great idea to give your baby lots of cues that it is time for sleep.

3) Teach your baby to self-settle

The best way through the regression is to teach your little one to self-settle. Once your baby falls asleep without any sleep props (dummy, rocking, feeding etc.), they are more likely to connect sleep cycles. It wouldn’t be fair to expect your baby to go back to sleep on their own during the night if they were fully assisted to sleep at the start of the night.

4) Teach your baby to re-settle

Re-settling is just as important of a skill, as getting your baby up after each 45 minute nap, teaches your little one that it is time to get up so there is no incentive for them to sleep longer. As the weeks go by, your baby will get more and more overtired due to the short day time naps and will start to wake up more frequently at night, so working on longer day time naps is important to avoid your baby getting overtired.

5) Get on top of the overtiredness

It is important to ensure your little one is not awake too long in between naps or you will have an overtired baby on your hands. When babies get overtired they get a second wind, which makes settling them to sleep very difficult. At 4 months of age the age appropriate awake window is roughly 2 hours, give or take depending on your baby. Further strategies to help with your overtired baby:

  • Early bedtime (as early as 6 pm)

  • Add a 4th nap if your baby is catnapping during the day

  • Do assisted naps for a few days (carrier, pram etc.) and work on self-settling at night

  • Reduce awake window for a few days

Cut yourself some slack during this difficult time. With a baby that barely naps during the day and regresses with their sleep during the night, you will find yourself anxious, stressed out and exhausted. You are not alone, this is usually the time when parents get in touch with me for help.

When you feel completely overwhelmed, it’s best to focus on improving night sleep first so both you and your baby have a chance to get some precious sleep. Once night sleep starts to improve you will have more patience to deal with the catnapping during the day.

Do you want access to my free 4 month sample routine including a feed and sleep schedule? Instantly download it here. Also includes a catnap routine if you’re not successful in getting your baby to take longer naps during the day.



Colten, H.R., Altevogt, B.M. and Research, I. of M. (US) C. on S.M. and (2006). Sleep Physiology. [online] National Academies Press (US). Available at: [Accessed 15 Apr. 2021].

MPH, E.F.-E., PhD (2018). The “Four-Month Sleep Regression”: What Is It, and What Can Be Done Ab. [online] babysleepscience. Available at: [Accessed 15 Apr. 2021]

Tham, E., Schneider, N. and Broekman, B. (2017). Infant sleep and its relation with cognition and growth: a narrative review. Nature and Science of Sleep, [online] Volume 9, pp.135–149. Available at:

The Science of Mom. (2012). The Importance of Self-Soothing to Infant Sleep (and how to support it!). [online] Available at:

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