What You Need to Know About the 4 Month Sleep Regression


4 month old sleeping despite sleep regression

Four-month-old babies are the cutest. By now, your baby is cute, chubby, and smiling. I mean, really. How cute is that? And, if you’re lucky, your baby’s even sleeping for several hours at a time. Naps might also get you some free time to get a quick shower or some basic things done. Until… you also have to deal with a wonderful surprise called the 4 month sleep regression. Welcome to the world of sleep regression, friend.

What is the 4 month sleep regression?

As with any other sleep regression, they’re triggered by your baby’s normal growth and reaching fun developmental milestones. While at four months of age, your baby’s personal developmental progress may vary, most four months old are just figuring out how to grasp and move things.

In other words, your baby has discovered that they can interact with the world. And it’s super weird for them. Your baby may also have learned to do some basic rolling over at this age, though not all babies have figured that out yet.

We’ll get to those milestones in just a minute – but first, some other super common questions that deserve answers.

When does the 4 month sleep regression start?

Generally, it starts somewhere around when your baby’s fourth month of life.

Now, some babies hit these milestones at 3 months. Some hit it at five months or even later. So there is some variation as to when the 4 month sleep regression can occur.

And if your baby was born premature, it’s more likely to hit at the adjusted four months of age, or four months after your original due date.

Do all babies go through the 4 month sleep regression?

No, not all babies will go through this. I’ve had some friends who said that their baby turning four months old was a magical time – where suddenly everything clicked and everyone got sleep.

That didn’t happen for us, which was kind of sad for us. But I was still elated for my friends who did get sleep!

Some of those friends didn’t have any big sleep regressions during their sleep training journey. But some had issues at the 8 or 11-month marks, as their baby became more mobile.

Other friends’ babies had massive sleep regressions at 4 months of age, but then had no issues at 8 months before having another massive regression at 12 months.

In other words, there’s almost no rhyme or reason to it. It’s like your baby is a cute little individual and they’re trying to figure this out, too. (Oh, wait. That’s exactly it!)

So, just because you skip one or several of the common sleep regressions doesn’t mean you’ll skip them all. Cross each bridge as you get to it, friend.

Now let’s cover the milestones that may have triggered this new, poor sleeping pattern that’s developed.

4-month-old developmental milestones

By four months of age, your baby has also finished the “fourth trimester” of development. Technically, that lasts until they’re 3 months old (for babies born at term). It’s the time when their brain makes huge leaps and bounds in development.

It’s also the time when they’re finally starting to get control of their cute, chubby little bodies.

In other words, they’ve just finished a lot of growing, developing, and now they want to use that!

By four months of age, each of my babies had figured out half of rolling over and could smile. Watching the baby make faces to get a reaction is one of my favorite “games” for four month olds. It’s such a cute age!!

As far as rolling over, if they were on their tummies, they could flop over onto their backs. And sometimes they could roll onto their tummies. But they weren’t very good at it.

They were, however, super excited about their new skill of moving. And it makes sleeping hard – especially when they roll over by accident while sleeping. Suddenly, their poor swaddled self is stuck on their tummy – and it’s terrifying.

What to expect during a baby’s sleep regression

Now, many babies by four months old may have figured out the whole sleeping through the night thing. They might even sleep for 6-8 hours at a time during the night. And, if your luck holds, you’re probably getting 2 or 3 naps during the day. Bless your lucky stars if they’re over an hour long, each!

Only, now your baby’s hit that 4-month-old sleep regression. So, what can you expect?

Our oldest boy had just figured out how to sleep for 3-4 hours in his crib by 4 months of age. Then, he forgot how to do that. Suddenly, laying him down meant his poor eyes popped open and he started screaming. He wiggled, he squirmed, and he became a baby Houdini, escaping from his swaddling blankets.

Then, he screamed. He cried, he fought falling back asleep, and he only calmed down once he was able to nurse

We tried several different types of swaddling blankets. The first several kinds were even easier for him to escape from – which meant he was sleeping even less!

We tried propping some little blankets under his swaddled arms to help him think he was being held. We put one of my smelly, breastmilk-stained t-shirts under his crib mattress so he’d feel like his mama was close.

It’s frustrating when everything you try seems to fail. Thankfully, once we figured out what didn’t work, we could move on to what did work.

Here are some of the ways we survived sleep regressions without going (too) crazy.

But here’s what actually helps your baby get back to sleep

After several awful, horrible, sleepless nights, we finally tried combining a few things – and it worked.

This is me giving y’all a heads up that there are partnered ad links in this post. As an Amazon Associate, I can earn from qualifying purchases. Please see my full disclosure policy for details.

First off, we finally found the most amazing, miraculous swaddling blanket – and it helped!

Then, we invested some time reading the most amazing sleep book of all time. And, we bought the only white noise machine that helps our picky sleepers doze off.

Those three things together helped us regain some semblance of our normal sleep.

So if you’re struggling to get your baby to sleep, here’s the short version of what helped from our sleep bible.

  • Move bedtime forward by 15-30 minutes. Tired kids need more sleep – and the only way they’ll get it is by going to bed sooner, because they can’t sleep in.
  • Make their bedtime routine more boring. For us, that meant cutting out the bedtime stories and songs.
  • Keep the bedroom dark, soothing, and quiet.
  • Use a night time diaper so that your baby can sleep longer without needing a diaper change.
  • After several days, your overtired, cranky baby should give way to your rested, happy baby.

Oh, and for naps? Do your best. It’ll be a rough few days, so hang in there. And if you’ve got family or friends you can ask for help? Go for it. Backup is always fantastic – as are naps for you!

How long does the four-month sleep regression last?

Sleep regressions can last anywhere from a few days to several weeks. Some can last up to a month. It just depends on what you’re doing to manage it.

So if you want to keep it shorter, make sure you’re sticking to a consistent, regular bedtime routine and sleep training plan. That way, you can keep it as short as possible. By baby #4, we’ve gotten our sleep regressions down from lasting weeks to just a matter of days. So it is possible!

How to survive the 4month sleep regression

Finally, I want you to remember something very important: our 4-month old baby boy was barely sleeping 3-4 hours at a stretch each night when this awful sleep regression hit. Then, he was up several times each hour, which was awful. I was devastated when, after implementing everything that the sleep book said to do, our baby boy didn’t suddenly start sleeping 12 hours solid at night. But, he did get back to sleeping his 3-4 hours.

Some overly-optimistic part of me was just sure that there would be something, somewhere, that could help transform our sleepless child into a solid sleeper. Well, I was devastated each and every time that it didn’t happen. In fact, the only thing that finally helped was our son turning one, weaning, and time. And that was true for each of our four kids

In other words, if your kiddos aren’t magical unicorns who sleep all night either, don’t get frustrated if they don’t become them overnight. It will take time.

The goal is to get your baby back to sleeping enough that everyone can function – and even be happy!

Now, when even that wasn’t enough for me to function, here’s what also helped:

  • Ask a friend or family member to spell you so you can take a nap. Even a quick 30 minute nap can do wonders, I promise!
  • Set up a schedule with your partner so that you can take turns getting more sleep – or going to bed earlier.
  • Cosleep with your baby. Just be sure to do it safely and responsibly!
  • Think outside of the box – ask other moms for ideas on how they survived this regression! (Need a support group? Come join my free sleep training support group on Facebook)

Because being a mom is hard, y’all. It’s worth it, but it’s hard. And the four-month sleep regression? It’s just a sample of what’s yet to come. So practice up, get prepared, and you’ll be able to breeze through the next several sleep regressions with relative ease. At least, compared to me! And, if you run into more trouble at the next sleep regression, remember this: I’ve been there. So I’ve got lots of ideas to help your family get back to sleep.

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Want more information on how to survive these awful sleep regressions? It’s been a popular topic, so I’ve written about it a fair bit. You’ll want to read all of the good tidbits there. And if you don’t see your question answered? Email me and I’ll see what I can do to help y’all get better sleep.

Kimberly C. Starr

I'm a ginger who loves reading, eating, being a nurse, spending time with my family, and writing about it all. I believe humor is the best medicine, followed very closely by chocolate and tacos. To read more about me, click here.

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