4-Month Sleep Regression: Causes, Signs, & How to Get Through It

If your little one was finally starting to sleep better and suddenly begins waking multiple times a night, taking short naps, or only sleeping in your arms, you're not alone. This sudden change is likely due to the 4-month sleep regression—a normal but frustrating part of infant development.

What is it?

The 4-month sleep regression is a natural shift in your baby’s sleep cycles as they mature, resulting in more frequent wake-ups and lighter sleep.

Why does it happen?

• Developing circadian rhythm and melatonin

• Learning new skills (rolling, babbling)

• Transition from newborn to adult-like sleep cycles.

Common signs:

• Frequent night wakings

• Shorter naps

• Increased fussiness or clinginess

• Trouble settling to sleep

• More night feedings.

How long does it last? Usually 2–6 weeks, but it may take longer if sleep habits don’t adjust.

Keep reading for expert-backed tips and simple solutions to ease the 4-month sleep regression and help your baby (and you) sleep better—starting tonight.

What Is 4-Month Sleep Regression?

Just when it seemed like your little one had settled into a more predictable rhythm, you might notice your 4-month-old waking up more often at night or struggling to fall asleep again after waking. Suppose your baby’s healthcare provider has ruled out any medical concerns. In that case, there’s a good chance you’re facing the 4-month sleep regression, a common and temporary phase of disrupted sleep during early infancy.

So, what is a sleep regression? A sleep regression in babies occurs when a previously well-sleeping baby starts waking more frequently, has trouble settling down at bedtime, or requires extra help to get back to sleep. These changes in sleep can be linked to rapid development in your little one’s brain and body. 

At around 4 months, one key developmental shift is the maturing of your baby’s sleep cycle. While newborns tend to drift in and out of short sleep intervals, four-month-olds' sleep schedules begin to follow more adult-like patterns, with lighter and deeper stages of sleep. That transition can lead to more frequent waking, especially if your baby hasn’t yet learned how to self-soothe, which is often at the heart of the infant sleep regression.

Do All Babies Experience a 4-Month Sleep Regression?

You may have heard a lot about the 4-month sleep regression, but not all babies go through it in the same way—or at all. So, do all babies go through sleep regression? Not necessarily. Some breeze through this stage with little disruption, while others may wake more often as their sleep patterns mature.

What Causes 4-Month Sleep Regression?

Sleep regression can happen at various ages, but it's especially common around the 4-month mark, right when your baby’s sleep cycle is starting to mature. As your baby begins to understand the difference between night and day and their internal sleep rhythms become more organized, they may start sleeping longer stretches at night and taking fewer naps during the day. 

Still, you might be left wondering: What causes 4-month sleep regression, and why does your little one suddenly seem so 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 a 4-month sleep regression; however, think of this as more of a learning curve rather than a “regression.” Other developmental milestones and significant changes may 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 return to sleep independently takes time for a young baby to learn. 

• Lack of consistent routine. At this age, routines are beneficial. A regular wind-down period before bed helps babies learn it’s time to sleep. If bedtime varies too much or if a baby always falls asleep while feeding, they might find it harder to connect the cues that lead to independent sleep. 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 behavior 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 old, they become more active, independent, and aware of their surroundings, which can sometimes make it harder for them to unwind at the end of the day.

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

When Does Sleep Regression Start?

Now that we’ve established what sleep regressions are and what their causes may be, you might be asking, “When do babies go through sleep regression?” Many parents first notice changes in their child's sleep around 4 months of age. This is often when the 4-month sleep regression begins, as your little one’s sleep cycles mature and start to resemble adult-like patterns. 

While research hasn’t shown sleep regressions to occur at a specific age for a baby, they may happen at different ages. The 4-month mark is a common time for disrupted sleep due to these biological and developmental changes.

4-Month Sleep Regression Signs

If your baby was sleeping more predictably and suddenly starts waking up more often, you may be spotting some common signs of a 4-month sleep regression. Around this age, your little one’s sleep matures, and temporary disruptions are common.

Here are some common signs of 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 have trouble sleeping for several reasons, including illness or teething. Contact your baby’s healthcare provider if you have any concerns.

Can the 4-Month Sleep Regression Affect Naps?

Absolutely. During the 4-month sleep regression, naps can become shorter, more irregular, or harder to settle into. So, if you're wondering, “Does sleep regression affect naps?”—yes, daytime sleep is often disrupted alongside nighttime wakeups. This shift is part of your baby’s maturing sleep cycle and usually improves as they adjust to new patterns.

How Long Does a 4-Month Sleep Regression Last?

When your baby’s sleep suddenly shifts, it can feel endless, but knowing that the 4-month sleep regression is a normal part of development may help ease some of the stress.

So, how long does a 4-month sleep regression last? It's likely that after a week or two, your baby will adjust to their new sleep cycle and start sleeping for longer stretches at night. At 8 to 9 months old, many babies will begin to sleep through the night. However, remember that every child is unique, and some may take more or less time to settle a consistent sleep pattern, while others may not experience a 4-month sleep regression at all. 

So, while the 4-month-old sleep regression may feel like it drags on, know that it’s temporary. With time, consistency, and a little patience, most babies settle into more predictable sleep, just when it feels like you need it most.

Signs 4-Month Sleep Regression is Over

The 4-month sleep regression is a phase where your baby's sleep patterns may temporarily become disrupted due to developmental changes. While the exact duration varies for each infant, many parents observe that their baby's sleep begins to stabilize after a few weeks.

Some signs that the 4-month sleep regression may be ending include:

• Sleeping for longer stretches at night

• Napping more consistently during the day

• Falling asleep with less fuss or needing less help

• Fewer night wakings.

Tips: How to Deal With 4-Month Sleep Regression

If your baby is suddenly waking more often, resisting naps, or struggling to fall asleep, you might be searching for tips for 4-month sleep regression. The truth is, there's no one-size-fits-all solution—but there are supportive, gentle ways to help your baby (and you) get through this phase.

So, how do you deal with a 4-month sleep regression? It begins with consistency, patience, and minor adjustments that adopt healthy sleep habits.

• Encourage self-soothing. One of the most helpful sleep regression tips is giving your baby a chance to fall asleep on their own. Instead of picking them up immediately when they cry, try waiting a short moment before responding. This helps your baby begin to practice self-soothing—such as sucking on their hand or calming themselves with small movements—as they adjust to their changing sleep cycle.

• 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, a bedtime lullaby, gentle rocking, a massage, or cuddling. During the diapering step, consider using Pampers Swaddlers, which helps keep baby 3x drier for all-night comfort, especially during this phase of frequent waking.

• Recognize the cues. Helping your baby fall asleep in their crib, rather than in your arms, can teach them to settle without extra help. If you’re wondering how to get through sleep regression, this slight shift can have a significant impact. Look for signs like rubbing eyes, fussiness, or yawning to time it just right.

• Feed before bedtime. Your little one’s body is growing rapidly right now, and hunger can contribute to night wakings. Offering a full feed just before bed may help them sleep a bit longer through the night.

• Maintain calm nights and active days. Another way to handle a 4-month sleep regression is to maintain peaceful nights—dim the lights, reduce stimulation, and use a quiet voice. During the day, expose your baby to sunlight and engage in play to help reinforce the distinction between daytime and bedtime.

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!

Whether you’re trying to figure out how to get through a 4-month sleep regression or just hoping for one decent nap, know this: You’re not alone, and this stage will pass.

Sleep Training a 4-Month-Old

By 4 months, many babies are ready to start learning how to fall asleep on their own. If you're exploring how to sleep train a 4-month-old, it's helpful to understand the different methods so you can choose one that feels right for both your baby and you.

Here are a few common approaches parents try when sleep training a 4-month-old, all of which vary in the level of parental involvement and comfort with crying:

• Sleep association (gentle method). Place your baby in the crib while they’re sleepy but still awake. If they cry, soothe them every 5 to 10 minutes with calm words or a gentle touch, without picking them up. Over time, they begin to link their crib with the comfort of falling asleep.

• Ferber method (moderate involvement). Also known as the Interval Method, this approach involves checking on your little one at set intervals. Offer brief reassurance without picking them up, gradually increasing the time between visits to help them learn to self-soothe.

• Cry it out method. Put your baby in the crib drowsy but awake and let them fall asleep on their own—even if they cry. This method involves no check-ins and may not be right for everyone, but some families find it effective.

Some babies may respond well to gradual reassurance, while others might find it more upsetting. It’s all about finding what works for your little one’s temperament—and your comfort. If you’re not sure how to begin or if sleep feels especially difficult, consult your baby’s healthcare provider for guidance before starting any method.

Can You Prevent 4-Month Sleep Regression?

Sleep regressions are a normal part of infant development, and not all babies experience them the same way. While you can’t fully prevent the 4-month sleep regression, building healthy sleep habits, such as a consistent routine and putting your baby down drowsy but awake, can make it easier to manage.

When to Consult Your Baby’s Healthcare Provider

Occasionally, sleep disruptions or a 4-month sleep regression may 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.

Self-Care Tips for Tired Parents

Sleep regressions can be exhausting for both you and your baby. While you're doing your best to support your little one, it's equally important to take care of yourself. These small, realistic steps can help you get through this tiring phase:

• Know your limits. If you're feeling depleted, it’s okay to ask for help or take a brief break. Taking turns with a partner, friend, or family member—even just for a quick break may help.

• Rest when you can. Even a short nap or lying down while your little one sleeps may help recharge you during the day.

• Practice mindfulness. Taking a few deep breaths, spending some quiet time, or taking a short pause during a hectic day can help bring your nervous system back into balance.

• Lean on tools that support your routine. If you're unsure where to start with sleep or just need guidance, tools like the Smart Sleep Coach by Pampers™ can help you create a consistent routine and understand your baby’s sleep needs over time. It’s one more way to take some of the guesswork off your plate.

• Be kind to yourself. This is a demanding stage, and it’s okay if your to-do list isn’t fully checked off. Doing your best—however that looks—is enough.

• Explore downloadable resources designed for parents. Pampers offers free, accessible tools to support your well-being in early parenthood. You can find checklists, simple tips, and other helpful guides in the New Parents Guide.

You’re not expected to do everything perfectly. Caring for your little one means caring for yourself, too. The more supported you feel, the more present you can be, one nap (or deep breath) at a time.

The Bottom Line

A newborn baby often comes with sleepless nights, but as your little one grows, they’ll likely start sleeping for longer stretches—and eventually through the night. Still, it’s not always a smooth transition. Around 4 months old, many babies experience the 4-month sleep regression, as their sleep cycle begins to mature, and they adjust to longer nighttime sleep periods.

While sleep regression can occur at any age, supporting your baby through this phase with healthy sleep habits, such as encouraging self-soothing, establishing a calming bedtime routine, and maintaining consistent sleep cues, can make a significant difference. With time, patience, and support, your baby will settle back into a better sleep rhythm—and you’ll get some rest, too.

Need a little extra support? Download the Pampers Rewards App to earn rewards on diapers and access educational content. Better sleep is ahead for both of you.

_{How We Wrote This Article The information in this article is based on 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.}