What is 4-Month Sleep Regression and How Long Does it Last?

Are you experiencing sleepless nights with your little one? If your 4-month-old was previously sleeping well but is now waking up frequently in the night and struggling to fall back asleep without your help, they may be going through the 4-month sleep regression. If you’re wondering how long 4-month sleep regression lasts, when it typically starts, and what signs to watch out for, keep reading to discover more about this common occurrence in infants. We’ve also got some sleep regression tips to help you and your little one get back on track when it comes to sleep.

What Is the 4-Month Sleep Regression?

Just when you thought you had put sleep deprivation behind you, your 4-month-old surprises you by waking up every hour or two, or multiple times during the night! If you’re wondering “Why is my 4-month-old not sleeping,” and your healthcare provider 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 4-month sleep regression is common.

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 around 4 months of age, their sleep pattern starts to become similar to that of an adult’s, 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!

related baby tool

Baby Growth Chart Calculator

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

Fill out your baby's details*:

What is your baby's sex?*

Boy Girl

This is a mandatory field.

Age (months)

This is a mandatory field.

Weight (lbs.)

This is a mandatory field.

Height (in.)

This is a mandatory field.

Head circumference (in.)

This is a mandatory field.

Track your baby’s growth

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

What Causes 4-Month Sleep Regression?

What causes 4-month sleep regression and when does it start? 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, what causes 4-month sleep regression, 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 4-month sleep regression, and keep track of their nap and sleep schedule, download the Smart Sleep Coach app by Pampers. Co-created by pediatricians 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.

4-Month Sleep Regression Signs

The following signs and 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 signs in your baby at 4 months or even older, 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 experience regression due to various symptoms, among them illness or teething. Contact your baby’s healthcare provider if you have any concerns.

Related Articles

What Is Sleep Training and How Do You Do It?

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 and what is the typical duration? 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!

“The act of falling asleep is a learned skill and your baby needs the space and time to practice. Four months is the perfect time to start sleep coaching. By delivering consistent bedtime routines that always end with your baby drowsy but awake, you’re setting your baby up for sleep success from an early age!” Says Mandy Treeby, Pediatric Sleep Coach and Co-founder of the Smart Sleep Coach by Pampers™ app.

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 four-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 and potential solutions.

Tips: How to Deal With 4-Month Sleep Regression

With some time and patience, and by following our helpful tips, you and your baby can learn how to get through the 4-month sleep regression and work toward a more peaceful night’s sleep.

• 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. Or for more step-by-step support with the Ferber method and others, download the Smart Sleep Coach app.

• 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.

• Recognize 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.

• Feed before bedtime. 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.

• 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, prioritize sunlight, play, activity, and wakefulness to encourage a better night’s sleep for your baby.

When to Consult Your Baby’s Healthcare Provider

Occasionally, sleep disruptions or 4-month sleep regression can be caused by sleep disorders or certain illnesses. Contact your child’s healthcare provider 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 apnea.

• Your baby has breathing difficulties.

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

The Bottom Line

A newborn baby often comes with sleepless nights, but as your little one grows, they will sleep for longer stretches and sometimes all through the night. But it’s not always smooth sailing! Around 4 months of age, a baby’s sleep cycle usually starts to mature. This 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, often cropping up at times of development and growth in your baby. To help your 4-month-old adjust and sleep better at night, you could 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 make a clear distinction between daytime and nighttime activity. With some time and patience, your little one will be nodding off—and you will too!

As you settle into your baby’s new bedtime routine, don’t forget to download the Pampers Club app and earn rewards on all those diapers 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 American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. 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.}