Sleep Regressions: Causes, Ages, and What to Do

Everything you need to know about a baby sleep regression. Learn about baby sleep regressions on through toddler sleep regressions. Know why they happen and how to help baby through them.

Sleeping baby

A sleep regression almost feels like a cruel joke. You have managed to be getting good sleep, or at least improved sleep, only to have that suddenly disappear!

I remember the first time I had a baby hit a regression. I scrambled, trying to figure out what mistake I had made and where I had gone wrong.

But progress in parenting is rarely if ever linear, meaning you rarely make strides without having events that also seem to be taking you backward.

Sleep regressions are one of those things. Despite your consistency, they still happen. And while the cause sleep issues and even frequent night wakings, they are a sign that your baby is getting older.

In other words, it isn’t your fault. Regressions are common.

Sleep is no different.

In this post, we will discuss what a sleep regression is, the signs of a sleep regression, causes of a sleep regression, how long a sleep regression will last, common ages for sleep regressions, and what to do about a sleep regression.

What is a Sleep Regression?

Simply put, a sleep regression is a time when your little one has a change in sleep patterns.

This will mean your little one is taking shorter naps, having a hard time falling asleep, wakes more often at night, and has a hard time sleeping in general.

During a sleep regression, you can have one of those sleep issues, a couple, or all of them.

This regression often seems to come out of nowhere. Everything will have been going very well and then your little one will suddenly not sleep as well.

With a true sleep regression, there isn’t anything you can do to fully stop the regression. You might be able to help make sleep better, but a true regression is something that takes time to end.

Everything to know about sleep regressions pinnable image

Signs of a Sleep Regression

You will probably find it quite obvious that your little one is having a sleep regression because sleep will not be as good as it was before.

These are some basic signs you have a regression happening:

  • More frequent waking
  • Can’t fall asleep or struggles to fall asleep
  • Won’t nap
  • Cranky or fussy during wake times
  • The age of your little one lines up with common sleep regression ages

Sleep Regression Causes

A true sleep regression is caused by a few things. The first thing to know is that a sleep regression is normal and a typical part of development.

Developmental Leap

The first cause of a sleep regression is a developmental leap. The book The Wonder Weeks is very helpful in letting you know when to expect major developmental leaps. Sleep regressions often coincide with these leaps.

In short, during a developmental leap, your baby or toddler is making great strides in some way. She may be developing her 5 senses more acutely. She might be growing more aware of the world around her. She may be developing physically, mentally, or emotionally.

These are all good things! But they do lead to sleep disruptions.

You can read much more about this in the post The Wonder Weeks and Sleep.

Developing New Skills/Developmental Milestones

Along the same lines, new skills can lead to sleep regressions. When your little one is learning how to roll over, crawl, walk, or talk (to name a few), it will lead to poor sleep.

>>>Read: How to Stop New Skills from Disrupting Naps and Sleep

Schedule Adjustment

Another common cause for a sleep regression is related to schedule adjustment.

A sleep regression can start when your baby or toddler needs a change to his/her schedule.

Your baby might need to drop a nap and thus stop sleeping as well at other points in the day. You might need to move to a four-hour schedule to help daytime naps. You might need to drop the dreamfeed to help with night wakings.

You might need to add more physical or mental activity into the daily routine. If your older baby is not sleeping well, staying active in the day during playtime will help sleep improve.

Your little one might also regress in sleep because a change has been made to the schedule that should not have been made. In that case, you would want to go back to the schedule you had before the regression started. You might even need to go back as far as two weeks. Read more about why here.

Growth Spurt

Another reason for baby sleep problems is a growth spurt. Your baby will wake up more often during a growth spurt, so sleep is disrupted.

Whether or not this is a true “regression” could be debated. But it happens on a time table and is a normal part of development.

I don’t necessarily categorize a growth spurt as a sleep regression. I would say it mimics a sleep regression, but it is simply a time your baby needs to eat more often and/or a higher quantity of food. This leads to less sleep.

At any rate, your baby could be not sleeping well because of a growth spurt.

>>>Read: Baby Growth Spurts: Everything You Need To Know


Your child might be experiencing a disruption to sleep that is caused by teething, pain, or sickness.

Just as with the growth spurt, I wouldn’t call poor sleep that is caused by teething, pain, or sickness a “sleep regression.” The poor sleep is a byproduct of the discomfort your little one is in.

But these are all very common causes of poor sleep and should have your consideration. Babies can start to have teething pain around 4 months old, and teething pain can disrupt sleep on into toddler years.

If I have a child over the age of one, I always consider an ear infection if they suddenly stop sleeping well.

With teething pain or sickness, you can often do a lot to help the cause of the regression so you can get your little one sleeping well again much faster than a true regression.

>>>Read: How To Maintain a Schedule When Your Little One is Sick

Schedule or Routine Disruptions

You can have what looks like a sleep regression if your little one has had a disruption to his typical routine or daily schedule.

If you recently traveled, it might take a bit for your child to get back on a solid sleep schedule. If you had a busy day away from home yesterday and naps didn’t really happen, your baby is overly tired today and will probably not sleep as well.

This looks like a sleep regression, but it is more of a sleep disruption and some solid sticking to your schedule will help get baby back on track.

But don’t be afraid of disrupting your schedule! Sometimes those disruptions are actually good. You simply need to accept that poor sleep can come when the schedule is disrupted and have patience as your baby gets back on track.

>>>Read: How To Expertly Manage Disruptions to Your Baby Routine

Length of a Sleep Regression

Are you wondering how long a sleep regression lasts?

The length of your little one’s sleep regression will vary dependent on the cause of the sleep regression. The short answer is your regression might last only a day and might last as long as 6 weeks. A true regression typically lasts 2-6 weeks.

Teething might only disrupt sleep for a day or two.

Disruptions from sickness can be a few days to a couple of weeks.

Growth spurts typically last a few days up to a week.

A regression because of a schedule disruption can take as little as a day to get back on track or as long as a month.

This will vary depending on how long your little one was disrupted (one day is very different from one week), how quickly you can adjust correctly for your baby, and how flexible your little one is.

When your little one needs a schedule adjustment, the length of the regression will vary depending on how quickly you identify the change that needs to happen and how long your little one takes to adjust to the change. It is very helpful to have an awareness of when things typically change for babies–I have a cheat sheet for you here.

When your little one is working on skills, sleep might be disrupted for a day or two or for a few weeks.

When your little one has a developmental leap happening, poor sleep can be as short as a few days to up to 4-6 weeks. But don’t worry! Most leaps are not that long.

Sleep regressions last a different amount of time based on the type of regression, but also on the disposition of your little one.

>>>Read: Sleep Disruptions You Will Face as a Babywise Mom

Common Ages for Sleep Regressions

There are many common ages for a sleep regression. Some are infamous, like the 4-Month Sleep Regression. Here are the typical ages for sleep regressions:

  • 4 month sleep regression
  • 8-10 month sleep regression
  • 12 month sleep regression
  • 18 month sleep regression
  • 2 year old sleep regression

The ages listed above are common sleep regressions. You might also see “sleep regression” tied with the following ages:

  • 3 month sleep regression
  • 6 month sleep regression
  • 9 month sleep regression
  • 15 month sleep regression

Let’s discuss some details on specific ages.

Sleep Regression Common Ages graphic

3 Month Old Sleep Regression

You might feel like you have a little sleep regression around 3 months old, and if you are looking at growth spurts, you could have regressions as early as 3-4 weeks old.

There is a wonder week around 3 months old that can lead to some troubled sleep. This isn’t super common, but if your baby is experiencing some sleep troubles at this age, it might be due to the wonder week or possibly a growth spurt.

4 Month Old Sleep Regression

The four month sleep regression is often regarded as the worst of the sleep regressions. I definitely see more questions on that age than any other.

This is the first big regression and it is also the longest. It typically lasts about 5-6 weeks. Babies are typically fussier during this regression, or developmental leap, than any other.

The regression at this age is caused by Wonder Week 19. Huge changes are happening for your baby during this leap.

You also might have a growth spurt going on at the same time, can have teething pain this early, and can have some disruptions caused by new skills.

>>>Read: Everything You Need To Know About Wonder Week 19

6 Month Old Sleep Regression

There is a big growth spurt at 6 months old, so you might find baby has a sleep regression at this age. Your baby might also need to drop a nap, drop the dreamfeed, or move to a 4 hour schedule at this age.

You also can have new skills happening, teething, and separation anxiety. Some believe babies this age can also have night mares.

8-10 Month Old Sleep Regression

This regression is tricky because it can start at any point in this 8-10 month old period. This is why you will see talk on the 8 month old sleep regression, 9 month old sleep regression, and 10 month old sleep regression

. If a baby started at 10 months, you could even see some asking about an 11 month old sleep regression.

But it really is just one regression that hits babies at different ages. The 8-month sleep regression is the same as the 10-month sleep regression.

This regression can be attributed to new skills, teething pains, language explosion, and separation anxiety.

A lot of milestones are met in this 8-10 month old time frame.

I also see many babies needing a change to the schedule in this time frame. They should go down to 2 naps around this age if it hasn’t happened yet.

When going to two naps, you should have an earlier bedtime for at least a couple of weeks if not longer. If this doesn’t happen, you might have night wakings.

Many babies also need more mental and physical stimulation during wake time activities around 9-10 months old. The world alone is not stimulating enough anymore.

Baby needs new, stimulating toys and to be exposed to more in the day. While you can still overstimulate a child this age, you are more likely to understimulate unless you are intentional with your time.

There is also a big wonder week that starts around 36 weeks and can go as long as 40 weeks old.

>>>Read: How to Manage Separation Anxiety in Babies

12 Month Old Sleep Regression

This is an age when there are more skills happening, teething happening, and sleep needs shifting.

The 12-month sleep regression is not a super noticeable regression for many babies and you might just glide right past this.

Some parents mistake this regression and short naps as a sign to go to one nap, which is an example of changing the schedule incorrectly and leading to sleep problems.

You will want to stick with two naps for one-year-olds, but you might need to start shortening naps. You might have a short morning nap a long afternoon nap, a long morning nap and a short afternoon nap, or you might just shorten both naps a bit.

12-month-olds can sleep with a stuffed animal or lovely. This might help give them something “to do” when they go down for a nap before they fall asleep or something to play with when they wake up.

Read more in the post Dropping the Morning Nap Transition Time.

>>>Read: What To Do When Your Pre-Toddler is Taking a Short Morning Nap

18 Month Old Sleep Regression

This regression can be caused by a need to drop to one nap a day as well as teeth coming in.

You might not have a regression at this age if you had one sooner for the same reasons. Your toddler may have needed to drop to one nap earlier. This can commonly happen around 15 months old.

And not all toddlers have a noticeable regression at this age.

>>>Read: 18 Month Sleep Regression: How to Help

>>>Read: Dropping the Morning Nap Full Guide

2 Year Old Sleep Regression

After the 4 month regression, the 2 year old sleep regression is the regression I see the most questions about.

Most toddlers will have some sort of regression around this age. This can be caused by major transitions, potty training, increased independence, increased curiosity, nightmares, molars coming in, moving out of the crib, and needing a schedule change, to name a few.

Read all about the Two Year Old Sleep Regression here. You can read about what to do when your two year old has sleep problems in this post. If your toddler is refusing to nap, read this post.

Preschooler Sleep Regressions

If you are having trouble with a preschooler sleep, check out Nap and Bedtime Concerns for Preschoolers.

What To Do When You Have a Sleep Regression

When your little one is having a sleep regression, follow these tips.

Address the Cause

You want to identify and address the cause of the sleep regression. If your baby is hungry, you want to feed him.

If your infant needs a schedule change, you want to change it. If your toddler needs his nap shortened, you want to shorten it. If your little one is having teething pain, some medicine and comfort can get naps right back to normal.

Not all causes can be “addressed,” but if this regression can be, take advantage of that.

Understand Baby’s Sleep Cues

So much of getting sleep right is having your wake time length correct. Sleep cues can help you get it right.

Your baby probably needs a much shorter waketime length than you think. It will probably even be shorter than what you see advised in popular baby sleep groups online (including Babywise groups). Check out Optimal Waketime Lengths for help on this.

Wait to Respond

Sometimes your baby will be listless while sleeping, but that doesn’t mean she is done sleeping. It is wise to wait 10-15 minutes when your little one wakes up earlier than expected and see if she will resettle on her own.

There will be times it is clear to you that you need to go to baby immediately, but if baby does not need you right away, many times if you wait 10-15 minutes, baby will go back to sleep.

Avoid Starting Habits You Don’t Want to Continue

It is tempting to start a bad habit during a regression. You might want to rock your baby, introduce a pacifier, or feed your baby to sleep.

If these are things you want to do and have done, then that is fine. But if those are habits you don’t want to continue, do not start them.

>>>Read: What to Do When Your Toddler Cries at Nap Time

How To Prevent or Stop a Sleep Regression

Some regressions will happen no matter what, but there are things you can do to help prevent other regressions or at least minimize the disruption a regression can cause.

Have a Solid Routine and Schedule

Consistency is king. It is much easier to find and address a cause if your routine is solid. A solid routine takes the guesswork out of a lot of things.

Have a bedtime routine and a nap routine. Keep track of your schedule. Watch for patterns.

Sleep Train Baby

Sleep training is a very helpful way to avoid major sleep regressions. Choose your favorite baby sleep training method and help baby be an independent sleeper.

Remember the sleep cycle and that a baby will wake every 45 minutes. If she can sleep independently, she can go back to sleep at this time rather than needing help.

My favorite sleep training method is a gentle sleep training method. See how to do it here.

Have Healthy Sleeping Habits

This goes along with having the schedule and having baby be able to self-soothe, but you want to make sure baby has healthy sleep habits.

In addition to a consistent routine and ability to sleep independently, have a solid sleep routine. Avoid unnecessary props. Have a consistent morning wake up time and consistent bedtime.

Use a White Noise Machine

If you do not already, use a white noise machine for your baby. This can help prevent baby from waking up because of a loud noise or older sibling in the house.

Tips from Readers

Here are some tips readers of this blog have shared:

Yooli said: “The number 1 thing for us was consistency. Bad naps, taking forever to fall asleep, whatever. We might tweak the schedule to get an overtired child down earlier, but we stuck to the schedule for the most part. If the kid sat in the crib and kicked the wall for an hour during nap time, fine. You still need to rest kiddo. In the middle of the night, we usually went in to comfort after waiting a few minutes, especially after the child was older and could call for us. But we never pulled the child into bed with us and we didn’t cosleep with them. There were some particularly bad nights when we would have to go in there 3-4-5 times a night and finally hold the child in a chair until they were asleep or near asleep and transfer, but we would always put them back in their crib or bed, reassure them, and leave.

I am absolutely convinced that sticking to a schedule made our kids get through and out of sleep regressions faster than most children. Neither of my boys really had that dreaded 4 month regression to the degree you hear moms lament about where they go on and on for months. 45 minute naps, crabbiness, night wakings, sure. But the HABIT of sleeping was already ingrained in them so even during regressions, they slept better than most kids and really helped their brains develop that much faster and get through those phases faster. And then when it was over, 2-3 hour naps and 12 hours overnights kicked right back in and they went right back to where they needed to be. Even now with my oldest going through the trying three’s, he needs his sleep more than ever – particularly his afternoon nap! Its something that is so restorative and soothing to his moody, crabby little soul right now, even when he insists he doesn’t want to nap. He might protest for a few minutes, but then goes down and goes to sleep. Why? Because its just been a part of his routine his whole life and he doesn’t know any different. Its always been non-negotiable.”

Ashley said: “A sleep regression is something all babies must go through. It’s not a reflection on you, especially if you have been consistent to this point. Regressions feel a lot longer than they actually are. I listened to a lot of crying during regressions, and sometimes I just had to take the baby and go to Target. Seriously, I bought a lot on clearance 😉 That said, regressions for my family were a time to stay consistent, but also allow us the freedoms to go places and do things in order to get things done and keep the normally crying baby entertained. They are maddening, they are intense, but they are temporary. Take the good you get during regressions! Once it is over, as it will certainly reach an end, life will feel perfect and beautiful”

Julie said: “Hang in there, and consider a schedule tweak!”

Carrie said: “It won’t last forever–unless you start bad habits, like feeding to go back to sleep or bringing baby to your bed. Those may work, but it’s really hard to stop later on. Give it a week or two to sort itself out before changing up anything big time. It might be a leap or light shining through a window. It could be a schedule problem, but be patient and let your baby work it out.”


This post has outlined all you need to know about infant sleep regressions as well as toddler sleep regressions. They are not fun for parents, but they are very common as your little one develops.

It is important to note that not all sleep problems or fussiness can be explained by a sleep regression. Read The Complete Guide to Troubleshooting Short Baby Naps for help on fixing nap problems and How To Solve Your Baby’s Nighttime Sleep Issues for fixing night wakings.

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This post originally appeared on this blog July 2020

2 thoughts on “Sleep Regressions: Causes, Ages, and What to Do”

  1. Please help. Our daughter recently turned 2 and for the last 7 weeks we have struggled with all things sleep, which turns into attitude, which turns into my husband and I getting frustrated, which just makes everything worse.

    Before this all started, she was on a 7:30-7:30 schedule with a nap from 12-2. She went to bed perfectly, rarely fussed, napped well, was so happy.
    Now she wakes up anywhere from 5-6, we cannot get her back to sleep, which messes up her nap, which messes up bedtime.
    She refuses to take a nap most days and the whole “rest time” is spent getting her back to bed.
    Bedtime is usually started at 7 now and will go on for several hours with her climbing out of bed, screaming, throwing her pacis (which we don’t give back to her until she climbs out of the bed for them), angry growling, etc.
    All day long she cries and whines and yawns and rubs her eyes but refuses to sleep.
    She is overtired, she is cranky, and I desperately want to help her.

    I have tried literally everything and we are at a loss.

    My only other idea is to lower the crib again, and make it so she can’t climb out. I have no issues with her CIO at this point but she won’t because she isn’t staying in her room so we always have to interact with her.

    Please, we are desperate.


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