All About the 4-Month Sleep Regression: Causes and How Long it Lasts

Just when you thought your baby was ready to sleep through the night, you may be faced with just a few more sleepless nights. If your 4-month-old was sleeping well but now wakes up in the night and can’t fall back to sleep alone, the term ‘sleep regression’ may be one you’ll want to become familiar with. Read on to learn more about 4-month sleep regression, its causes and signs and some tips on how to deal with this challenging phase.

What Is 4-Month Sleep Regression?

You may have thought that your sleep deprivation was a thing of the past, but now your 4-month-old surprises you by waking up multiple times during the night! If you’re wondering ‘Why is my 4-month-old not sleeping,’ and your doctor has ruled out any medical issues, your little one may be experiencing what is sometimes called 4-month sleep regression. Sleep regression is when your little one stops sleeping as well as they did before. They may have trouble falling asleep at bedtime, or they may cry out for your attention when they wake up and have difficulty falling back to sleep by themselves. This sleep issue may appear during a period of growth or development in your baby. And around 4 months of age is when a baby’s brain and body are rapidly developing and they’re adjusting to these changes – which is why there is often a 4-month sleep regression. One of the big changes your baby may be going through around 4 months is the development of their sleep and wake cycle. Newborn babies sleep in short intervals, but at around 4 months of age, their sleep pattern starts to become similar to that of an adult, meaning they may sleep for longer periods of time at night. But of course, your little one may take some time to adjust to these changes and that’s when 4-month sleep regression may pop up! If you’re curious about what happens during a 4-month sleep regression and you’re looking for support, start your free sleep consultation with the Smart Sleep Coach by Pampers™ and get a personalised sleep plan for your baby.

related baby tool
Baby Growth Chart

Baby Growth Chart Calculator

Keep an eye on your baby’s height, weight, and head circumference to average growth with our simple tool.

What is your child*
This is a mandatory field.

This is a mandatory field.

This is a mandatory field.

This is a mandatory field.

This is a mandatory field.

*Input details of your baby’s last measurements **Source: World Health Organization

What Causes 4-Month Sleep Regression?

Sleep regression can occur at any age, but 4 months old is often when a baby’s sleep cycle is maturing. As babies learn the difference between night and day, and their sleep-wake cycles become more regulated, they start to sleep longer at night and take fewer naps during the day. So, why does the 4-month sleep regression happen, what factors can lead to sleep issues and sleep regression in general and why is your little one restless at night?

  • Developmental changes. As mentioned above, at around 4 months of age, your baby’s sleep cycle (circadian rhythm) starts to mature, and they begin to adjust their sleep patterns. This can temporarily disrupt their sleep, causing 4-month sleep regression; however, think of this as more of a learning curve rather than a ‘regression.’ Other developmental milestones and big changes can lead to 4-month sleep regression, such as growth spurts, teething and motor developments – your little one is working hard!

  • Not able to self-soothe yet. All babies (and all older children and adults, too) wake up for short periods throughout the night. The ability to soothe themselves and go back to sleep on their own takes time for a young baby to learn.

  • Poor routine or lack of routine. Doing the same thing every night helps your baby understand that bedtime is near and it's time for sleep – especially around 4 months when your little one may be adapting to their new pattern.

    • A relaxing routine and being put to bed when they’re sleepy but still awake helps them develop positive associations with bedtime.

    • Conversely, if you make a habit of rocking your little one to sleep in your arms, or letting them fall asleep while they’re feeding, this will become the expected behaviour every night and every time they wake up between sleep cycles in the middle of the night.

  • Increased alertness and activity. When your baby is around 4 months, they become more active, independent and aware of their surroundings, sometimes making it harder for them to unwind at the end of the day.

  • Medical causes. Often, sleep problems in babies are related to a medical or health issue, such as colds or ear infections, teething and constipation. If your little one isn’t sleeping well, look out for symptoms of illness.

To help you deal with your baby’s sleep disruptions, and keep track of their nap and sleep schedule, download the Smart Sleep Coach app by Pampers. Co-created by paediatricians and sleep experts, this app can make it easier to adapt to a bedtime routine, assist with sleep training and help you deal with sleep regression if it arises.

Do All Babies Have 4-month Sleep Regression?

It’s important to remember that just like us adults, all babies are different when it comes to sleep. At this age, they’re just getting started working on developing their own sleep patterns. So, if you’re wondering, ‘does every baby have a 4-month sleep regression?’ the short answer is not necessarily. Remember, also, that things like growth spurts and teething can affect sleep patterns, and these can occur at different times, not always right at the 4-month mark.

4-Month Sleep Regression Signs and Symptoms

The following changes in sleep habits may indicate that your 4-month-old is experiencing 4-month sleep regression:

  • Taking a long time to fall asleep at night

  • Waking up frequently during the night

  • Increased fretfulness

  • Disrupted daytime naps.

If you’ve noticed some of these 4-month sleep regression symptoms in your baby (at any age), your little one may be going through a period of sleep regression or 4-month sleep regression. However, your 4-month-old baby can wake up and have trouble sleeping for a number of reasons, among them illness or teething. Contact your baby’s doctor if you have any concerns.


Baby Sleep
Creating a Good Bedtime Routine

When Does 4-Month Sleep Regression Start?

Sleep regression can hit at any time, not only at the 4-month mark. Just think about yourself, for example. If you’re going through a stressful period, you may find it more difficult to fall asleep or stay asleep. So, 4-month sleep regression can happen early, it just depends on what’s keeping your baby up a night. Teething? Changes in routines? A growth spurt? There are a variety of factors that could kickstart a sleep regression. Remember, sleep problems are a normal part of growing, and they’ll eventually pass.

How Long Does 4-Month Sleep Regression Last?

Even one sleepless night can be a struggle, and a week or two without proper sleep can make a good night’s rest feel like a distant memory. But you’re not alone in this! Most parents have experienced sleepless nights with their little ones. So, when does a 4-month sleep regression end? It's likely that after a week or two, your baby will adjust to their new sleep cycle and begin to sleep for longer stretches at night. At 8 to 9 months old, many babies will begin to sleep through the night. But remember, every child is different, and some may take more or less time to settle into a consistent sleep pattern, while others may not experience 4-month sleep regression at all. Studies have shown that teaching and forming good sleep habits while your baby is young is easier compared to when they’re reaching toddlerhood. It just takes a little (or a lot) of time and patience – but better sleep is on the horizon!

What Happens After 4-Month Sleep Regression?

Your little one is going through lots of growth and changes, from teething to brain development, and so much more. And, their sleep patterns are likely to go through lots of changes, too. Try to be patient and understanding as your baby goes through various stages of growth. It may not be the last time they experience a sleep regression.

Can You Prevent 4-Month Sleep Regression?

As mentioned above, sleep regression may be connected to developmental changes in your baby, and around four months is a time when their sleep cycle is starting to mature. It's not possible to predict if your baby will go through a 4-month sleep regression or sleep regression at any age. There are, however, ways of helping your little one sleep better at night and these may provide potential solutions for your baby's sleep issues. Keep reading for some 4-month sleep regression tips.

How to Get Through 4-Month Sleep Regression

There may not be a ‘one-size-fits-all’ solution when it comes to 4-month sleep regression; however, there are some things you can try if you’re wondering how to help your little one sleep better during this tricky period. With some time and patience, and by following our helpful 4-month regression tips, you and your baby can get through this and work toward a more peaceful night’s sleep.

  1. Encourage self-soothing. Many babies have difficulty falling back to sleep by themselves because they rely on their parents to soothe them. Instead of rushing to your baby the minute they cry at night, try gradually taking your time more and more each night, a method known as the Ferber method or graduated extinction. This gives your baby a chance to fall asleep on their own and learn self-soothing techniques when they’re adapting to their new sleep pattern, such as sucking on their hand or thumb.

  2. Create a bedtime routine. Following a consistent nightly ritual just before bedtime can help your baby relax and establish good habits for the future. Your bedtime routine could include a warm bath, a story or a bedtime lullaby, gentle rocking, massage, or cuddling.

  3. Recognise the cues. When putting your baby to bed, make sure they’re sleepy but still awake. This may allow your 4-month-old to learn how to get to sleep on their own. Cues that your little one is feeling drowsy include yawning, crying, rubbing eyes, pulling ears and acting fussy.

  4. Feed before bedtime. One way to help 4-month sleep regression is by ensuring your little one is well-fed throughout the day and feeding them right before bedtime can help prevent them from waking up hungry during the night. Your 4-month-old is going through a lot of growth and development right now, so they may be hungrier during this period.

  5. Keep nights calm and days active. Try to keep evening and bedtime a calm and quiet time with very little stimulation for your baby. You could try dimming the lights, speaking in a soft and soothing voice, and avoiding any screentime or stimulating toys. During the day, prioritise sunlight, play, activity and wakefulness to encourage a better night’s sleep for your baby.

When to Consult Your Baby’s Doctor

Occasionally, sleep disruptions or 4-month sleep regression can be caused by sleep disorders or certain illnesses. Contact your child’s GP or health visitor if:

  • Your baby is extra irritable and can’t be soothed. This may be due to colic, a common cause of sleep disruption and fussiness.

  • You suspect your baby’s 4-month sleep regression is due to something such as an ear infection, reflux, or sleep apnoea.

  • Your baby has breathing difficulties.

  • It’s difficult waking your baby up from their sleep.


Although there’s no standard length of time for a 4-month sleep regression, you may find that it lasts about a week or two. Check out the tips in our article to help give your child (and yourself) the best night’s sleep possible.

The Bottom Line

Sleepless nights go hand in hand with having a newborn baby, but as your little one grows, they will sleep for longer stretches of time, and sometimes all through the night! But it may not always be smooth sailing. At around 4 months of age, a baby’s sleep cycle usually starts to mature, which can occasionally cause a disruption in their sleep – often called 4-month sleep regression – as they adjust to a new sleep pattern and learn to sleep longer throughout the night. Sleep regression can occur at any age, and it often crops up during times of development and growth in your baby. To help your 4-month-old sleep better at night, it’s a good idea to try encouraging them to self-soothe, create a relaxing bedtime routine and environment, put them to bed when they’re drowsy but not asleep, feed them before bedtime and do your best to help them understand the difference between daytime and night-time activity. It may take a bit of time and patience, but eventually, your little one will be nodding off – and you will too! As you start to get comfortable with your baby’s new bedtime routine, don’t forget to download the Pampers Club app, so you can save big on all those nappies and wipes your little one goes through!

How We Wrote This Article The information in this article is based on the expert advice found in trusted medical and government sources, such as the National Health Service (NHS). You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.

chatbot widgethand
Cookie Consent