The Sleep Regression Timeline by Age

Last Updated: 
May 15, 2023
 minutes read
Written by
Mandy Treeby
Chief Baby Sleep Consultant
Medically reviewed by
Elissa Gross, DO
Board Certified Pediatrician & Lactation Consultant

As a parent, few things are more precious than the sight of your little one peacefully sleeping. However, even the best sleepers can experience disruptions in their slumber due to sleep regressions. These temporary periods of sleep disturbance often occur around key developmental stages, such as at 4 months, 8-10 months, 12 months, 18 months, and 2 years of age.

To help you navigate these challenging phases, we've put together a comprehensive guide outlining the sleep regression timeline. In this article, we'll explore the different stages of sleep regressions, the developmental milestones associated with them, and provide practical tips for managing these disruptions, ensuring that both you and your baby can successfully sail through this journey towards restful nights.



What is a Sleep Regression

A sleep regression is a temporary phase during which a baby who has been sleeping well for an extended period suddenly experiences disruptions in their sleep patterns, waking up frequently throughout the night.

Situations like these can leave parents feeling exhausted, bewildered, and concerned. Imagine, your little one was sleeping soundly through the night, and suddenly, they wake up randomly in the night; then again the next night, and the night following… You get the idea... and we get it too–it’s tough!

What’s more, regressions can appear and reappear over the course of your baby’s first two years, often at predictable intervals. That’s why knowing what to expect – and when – can really help you prepare and cope with sleep regressions.

Why Do Sleep Regressions Happen?

In addition to coinciding with growth spurts, sleep regressions almost always coincide with big developmental leaps, like learning to crawl or use a spoon, as well as increased physical activity, speech development, increased awareness, emotional development, and independence. That’s why we often refer to them as sleep progressions.

These are new, exciting skills and experiences that can distract your baby from the business to sleep. And, hey, can you blame them? If you just learned about hands, you’d want to stay up all night using them, right?

Understanding these milestones, and when they happen, can make the cause of your baby's sleep regression easy to spot, and easier to prepare for. So, when you’re looking for extra sleep support that won’t break the bank, look no further than the Smart Sleep Coach by Pampers App, Parents swear by it

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What are the Signs of Sleep Regression?

Regardless of when a sleep regression happens, common signs that your baby is experiencing a sleep regression include:

  • Your baby’s naps are shorter
  • Your baby is refusing to take naps
  • Your baby’s naps are longer, but night sleep is shorter
  • Your baby protests at bedtime
  • Your baby wakes up crying at night
  • Your baby can’t fall back to sleep after waking mid-sleep
  • Your baby is more fussy than usual around nap or bedtimes.

When Do Sleep Regressions Happen?

Every baby is different, and thus, no single timeline will precisely correspond to your baby's individual development and experiences. However, there are commonly observed periods when babies tend to experience sleep regressions: typically at 4, 8, 12, 18, and 24 months. Although there may be other sleep regressions, these are the most frequent and often the most long-lasting.

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Common Sleep Regressions to Watch For

4 Month Sleep Regression:

The first and most common sleep regression occurs around 4-months of age. It occurs when your baby is developing new physical and mental skills, including sitting up, using their hands more, smiling, and making new sounds – all of which is very exciting to them and may distract them from their sleep.

But there’s something else unique about your 4-month-old, their natural circadian rhythm is more mature than ever.

The circadian rhythm is your baby’s natural, biological sleep regulating process that helps them understand the difference between day and night and when to sleep.  Though natural, this process takes a few months to form – that’s why sleep is so disorganized for newborns. That’s also why while you can start healthy sleep habits from day one, we recommend you only  start sleep training around 4-months of age.

Interestingly, a 2007 medical study of found that nearly 30% of infants experience a sleep regression at four months, and one of the potential reasons they found was delayed development of circadian rhythms. The other explanation: later than ideal bedtimes.

If you suspect your baby’s schedule is off, bedtime is too late or for any reason they don’t seem to be getting through that 4-month sleep regression, take this  Free Sleep Assessment to access your personalized sleep plan that will not only diagnose the issues you need to solve, it will support you every step of the way help your baby fall asleep faster and stay asleep longer.  It’s so effective that most users see results in a week or less – which means their babies are sleeping better, faster – and so are their parents!

4-month sleep regression

4-month Sleep Regression

8 Month Sleep Regression

While most 8-month-olds can sleep through the night – and many are sleeping 11-12 hours at night, especially after sleep coaching – a sleep regression at 8-months is very common, though sometimes it occurs a little closer to 9-months, which is why it’s often referred to as the 9-month regression.

The 8-month or 9-month regression happens because of all the many milestones your baby’s achieving: they’re teething; they’re learning to crawl, and their trying to sound out words – all of which can be exciting and disrupt their sleeping.

But the main reason behind the 8-month-old regression is separation anxiety.

That may sound a bit unnerving, however a baby experiencing separation anxiety is a totally normal, healthy, and a very positive element of their development.

Why is separation anxiety in baby’s a good thing?

Because it shows they’re learning object permanence: that is, they understand that things still exist even when your baby can’t see them anymore. Before 8-months, it was very much “out of sight, out of mind” for your baby.

Now, however, they understand that when they can’t see something or someone, namely: you, that thing or person is somewhere else, doing something else – and they want to know what, where, and why. Therefore, when your baby wakes at night from an  8-month-sleep regression, they may realize you’re not there and cry out for you because they miss you.

How to Handle Separation Anxiety in Babies

One great way to alleviate separation anxiety in your baby is to get them used to being alone. You do this by playing a fun game called “I’ll be right back!”

To do this, place your baby in a safe space and say “I’ll be right back.” Then, step out of sight for a minute or two before returning and saying, “I’m back!”

This exercise shows your baby that all is well if you leave and that, yes, you will always return while also increasing their “alone endurance” by steadily increasing the amount of time you step away.

Another way is to use consistent phrases when you leave and when you return – this repetition helps your baby understand that you are coming back since they’ve heard you say that before and you returned shortly after.

8-month sleep regression

8-month Sleep Regression

12 Month Sleep Regression

Oh, baby!

Your 1-year-old is marking some major milestones: they can stand and may even be cruising around by using chairs and couches as support; they can also grasp objects, understand and mimic simple words and are more and more curious about this great, big world around them. They may even have taken, or be taking their first support-free steps!

This is all incredible – but it can also be incredibly disruptive for their sleep.

Also, while we recommend starting sleep training at 4 months, it’s truly never too late to start sleep training. And even if you sleep trained in the past, it’s often a good idea to reapply the same approach when a regression is getting the better of your sleep.

Not sure where to start? Download the Smart Sleep Coach by Pampers™ App, this top-rated sleep app is helping parents everywhere get their babies sleep on track.

12-month sleep regression

12-month Sleep Regression

18 Month Sleep Regression

Similar to the 12-month sleep regression, the  18-month sleep regression coincides with major mental, verbal, and physical milestones, including walking independently, adding a few words to their vocabulary, learning to bring food and water to their mouths, climbing, and following directions – or, at times, not following directions as they develop their sense of self and independence.

So, yes, your 18-month is experiencing a lot of new things, and, as with other sleep regressions, this can be far, far more exciting than boring old sleep. They’re testing their boundaries – and this may test your patience.

While we understand this may be frustrating, it’s entirely okay for you to take a second to decompress in stressful times. Simply place your baby in a safe space and step away for a moment to recenter yourself.

18-month sleep regression

18-month Sleep Regression

24 Month Sleep Regression

The last big sleep regression typically happens around the 2-year mark, when your baby is talking more, walking more, and just experiencing more.

Though the symptoms of this sleep regression are the same, their expression can be a bit of a doozy because your baby is much more vocal and assertive than ever. They can – and will – say “no” to protest bedtimes and may even throw a tantrum.

As frustrating as this may be, rest assured this is normal: your two-year-old is simply testing their independence. (Those meditations we mentioned come in particularly handy at this time.)

Luckily, this too shall pass – and even faster if you’ve been sleep training. That’s because the more consistent your baby’s bedtime routine is prior to this point, and the more consistent you can be with it now, the shorter their sleep regression is likely to last.

And remember, an earlier bedtime is always a good idea! Particularly if you feel this regression has led to your little one getting less sleep than usual.

In fact, a 2015 study sampled 425 two-year-olds and found that 21% of them went to bed past 10pm. Not surprisingly, that group reported more difficulty falling asleep at night and slept less overall. As with the 2007 study, this suggests what we’ve long known: early bedtimes play a crucial role in creating healthy sleep patterns in babies. That same study also suggests late naptimes can disrupt a baby’s sleep, which we’ve also experienced first-hand.

24-month Sleep Regression

24-month Sleep Regression

Coping with a Sleep Regression

Now that we understand when and why sleep regressions happen, let’s focus on how to manage and cope with sleep regressions.

Though some steps will differ as they age – for example, soothing teething isn’t always applicable at 4-months – most of these actions will help with any sleep regression, any time:

Keep Up Routines: Calm, consistent bedtime routines are the cornerstone of any sleep coaching practice. These quiet moments both soothe your baby before bed and create a predictable pattern that teaches them when it’s time to sleep, creating a habit that will serve them for years to come.

No matter how old your baby or what sleep regression you’re experiencing, maintaining your consistent bedtime routine can work wonders to reset your baby in these temporary setbacks.

Keep It Dark: Even a little bit of light can disrupt your baby’s sleep. That’s why we recommend installing blackout curtains in their sleep space.

Keeping the lights low has another benefit, though: it means your baby can’t be distracted by what they see in their room.

While this is less important during a 4-month sleep regression, it becomes more important as your baby grows and becomes more curious: a 12-month-old that can see their dinosaur toy on the shelf is going to have a harder time falling back to sleep than the baby who can’t see their dinosaur toy.

Wait a Moment:  As parents, we want to make sure our baby is happy and healthy at all times. When we hear a moan, cry, or gurgle, we want to check on it immediately. Sometimes that’s not best, though – sometimes going in to check on your baby will wake them more. Instead, wait a minute to see if your baby self-soothes themselves back to sleep.

What is Self-Soothing: Self-soothing is your baby’s natural ability to calm themselves to sleep or back to sleep if they wake up. Though this is a natural ability, sleep coaching strengthens it to ensure your baby can get back to sleep faster than without sleep coaching.

Low Lights/Low Voice:  If you do check on your baby, keep the lights low – or use a nightlight – and speak softly. You want to keep the energy calm and serene to prevent waking them further.

Read the full article on coping with sleep regression

Adjust Bedtimes:

Research suggests that babies with late bedtimes experienced more frequent night wakings and sleep regressions. These findings bolster other studies showing that baby’s need early bedtimes. So when in doubt, don’t offer an extra nap – shift bedtime earlier.

Address Separation Anxiety:  We mention this above, in the 12-month sleep regression section, but it’s worth repeating: playing games like “I’ll be right back” teaches your baby two things: one, they’re safe even if alone for a moment; and two, you will always return to them, your little ray of sunshine. It may sound silly, but we promise doing this during the day can really help your baby self-soothe at night.

Alleviate Teething Pain: If teething is disrupting your baby’s sleep, try using a teething ring, rubbing frozen fruit on their gums, or a cool, wet washcloth to soothe their discomfort. (Only offer these things when your baby can be supervised)

Revisit Sleep Training: Sleep coaching tunes the fundamentals of sleep (schedule, environment, routines and how your baby falls asleep) and harnesses the power of your baby’s circadian rhythm and scientifically proven methods, to teach them how to fall asleep independently. The act of falling asleep is a learned skill and a baby who has accomplished this will ultimately fall asleep faster and stay asleep longer - better sleeps for them, and for you.

Sleep regressions can disrupt this rhythm, temporarily throwing your baby’s sleep patterns off course. Revisiting your sleep coaching method where you last left off can get things back on track pretty fast. And of course, if you’re not sure where to start, take this Free Sleep Assessment and jump start your journey to better sleep with a personalized sleep plan.

For example, if you were doing the Chair Method of sleep training, and you were last 4 feet away from your baby’s crib, restart your method there, at four feet, and move back to five feet the next night, then six, and so on until you’re out of the room or your baby is falling asleep on their own.

Keep in mind, your baby is learning a lot about the world; sometimes a little refresher is all they need to “click” back into their sleep schedule.

Practice Self-Care: We want to reiterate that it’s 100% A-Okay for you to take some “me time” when stressed, frustrated, or you just need to catch your breath. This doesn’t mean you’re selfish or neglectful. It means you’re a human, and it will make you a better, more attentive and patient parent.

Parenting can be difficult, especially during sleep regressions, and taking a moment will let you recenter yourself so you can refocus on the important work ahead.

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Sleep regressions occur often during the first few years of life, most commonly at 4-months, 8-months, 12-months, 18-months and 24-months.

The most obvious signs are sleep disruptions (not related to teething or sickness) such as waking more often at night or having more difficulty falling asleep at bedtime and acting more fussy than usual.

Sleep regressions can last anything from 2-6 weeks. They tend to last longer when handled inconsistently.

It’s not so much that your baby fights sleep during a sleep regression, it’s more their developmental progressions (physical and mental) disrupting their normal sleep behaviors. For example, during the 8-month sleep regression it’s typical for babies to not want to go to sleep because they have developed the ability to miss you.

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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.


“Association between delayed bedtime and sleep-related problems among community-dwelling 2-year-old children in Japan,” Journal of Physiological Anthropology .

“Sleep of 4-month-old infants: bedtime, night waking and sleep problems,” Institute of Behavioral Health.

“2022 Updated Recommendations for a Safe Infant Sleeping Environment,” The American Academy of Pediatrics.

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