The 4 Month Sleep Regression Explained

If you’re reading this, you probably fall into one of two categories:

1. You have a newborn, and you’re already dreading the infamous 4-month sleep regression.
2. You have a 4- or 5-month-old and are wondering, “What happened to my great sleeper?!”

In today’s blog, we’re breaking down exactly what’s happening during the four-month sleep regression and sharing three practical strategies to help you navigate this phase and come out the other side feeling more well-rested.

WHAT IS THE FOUR MONTH SLEEP REGRESSION?

The four-month sleep regression isn’t a myth or a scare tactic—it’s a real developmental milestone. Perhaps you’ve been getting emails warning about the dreaded four-month mark, or maybe you’ve heard about it from friends. While it’s real, we encourage you to reframe it in a positive light.

What’s actually happening is that your baby is maturing and growing up, which is a good thing.

Newborn sleep cycles and Baby sleep cycles are completely different. Newborns have two sleep cycles that they rotate in and out of: deep/non-deep and REM/non-REM. That’s all they need during those early weeks.

Once we get to 4 months old, around 16 weeks from their due date, your child now develops fully mature sleep cycles just like us. These new cycles involve more complex stages that your baby transitions through during sleep. This marks a big milestone—they’re no longer newborns! Let’s celebrate the fact that your child’s sleep needs are growing and evolving.

If you’re in that awkward 3 to 4-month period where sleep feels unpredictable and things are changing drastically, don’t worry—we’re here to help!

Here are 3 tips you can start implementing today to navigate this transition and come out of the four-month period feeling more well-rested and confident.

How To Move Past The Four Month Sleep Regression

1: GET OUT OF THE SWADDLE

This might feel a little intimidating, but here’s why it’s so important to transition out of the swaddle:

Swaddles are a fantastic tool for newborns who can’t yet control their bodies, self-soothe, or manage the startle reflex. However, at 4 months old, your baby is no longer a newborn. You might be thinking, “But my baby still struggles with the startle reflex, so I can’t stop swaddling yet.”

The question to ask yourself is: How will my 4-month-old ever learn to use their body if we keep them wrapped up like a burrito?

Swaddles are wonderful for those early weeks, but by 8 to 12 weeks, it’s time to start transitioning their arms out of the swaddle, one at a time. If your baby is still swaddled at 4 months, we recommend moving to the cold turkey method—ditch the swaddle completely and transition them directly into a sleep sack.

We love traditional open-arm sleep sacks because they’re versatile, safe, and can be used well into your baby’s later months.

It’s important to transition out of the swaddle so your baby can learn to use their body.

When we sleep at night, we’re not stationary—we switch positions, place our arms under a pillow, sleep on our back or side, and adjust as needed. While it might feel strange to think of your baby being ready for that kind of control, they absolutely are!

By 4 months old, babies are beginning to explore how to use their bodies. They’re learning to manipulate themselves in the crib, roll from back to belly and belly to back, or even rest on their sides. These movements are both normal and essential for their development.

To ensure these movements are safe, it’s time to move out of the swaddle. Allowing your baby the freedom to move not only promotes healthy growth but also helps them develop the skills they need for independent sleep.

2: OFFER MORE NAPS IN THE CRIB

Step 2. Around the 4-month mark, your baby may lose the ability to easily transition from the car seat to the crib. Have you noticed that?

At this age, babies are much more aware—they’re no longer those sleepy newborns! With increasing awake times and changing sleep cycles, it’s the perfect time to focus on helping your baby nap more in their crib.

This transition also aligns with our blog post on moving from a bassinet to a crib, so be sure to check that out for additional tips. Now is the ideal time to make the move from a bassinet to a crib.

Naps in the crib are far more restorative than naps on-the-go, so prioritizing crib naps will help ensure your baby is getting the quality sleep they need during this developmental stage.

Newborns can only handle 60-minute awake windows, but guess what a 4-month-old can manage? An hour and a half to an hour and 45 minutes! That’s a significant increase, and it’s a great opportunity to focus on more naps in the crib. Why is this important? Crib naps help your baby connect sleep cycles, leading to more restorative rest.

That said, you still have a life, and you shouldn’t feel trapped inside your house! A balanced approach works best—aim to have at least half of your baby’s naps in the crib and the rest on-the-go. So try to focus on offering at least half of your baby’s naps in the crib and the rest can be on-the-go.

3: DITCH THE SLEEP PROPS

Yikes—this is probably the scariest step of all!

To help your baby sleep better, they need to learn how to fall asleep completely on their own. It’s time to start eliminating sleep props such as swaddles, pacifiers, rocking to sleep, or feeding/nursing to sleep—anything they currently rely on to drift off.

This is a big change and marks the key difference between a newborn and a baby. Newborns need help to get drowsy and fall asleep, but babies need to learn to do this independently. Removing sleep props is essential because it’s the only way your baby will sleep more fully, connect their sleep cycles, and enjoy longer stretches of rest.

Think about this: if your baby falls asleep using a prop—whether it’s nursing, rocking, bouncing, a pacifier, feeding, or a swaddle—they will come out of their sleep cycle looking for that same prop to help them transition into the next one. This can happen repeatedly throughout the night and during naps.

The good news? Your baby is ready to learn how to fall asleep independently. Teaching them this skill is one of the greatest gifts you can give—it sets the foundation for restful, independent sleep that will benefit them (and you!) for years to come.

CONCLUSION

Step 1: Ditch the swaddle.
Start this step right away by transitioning your baby to an open-arm sleep sack. It’s important to move out of the swaddle so your baby can begin exploring their body, which is essential for their development and safety.

Step 2: Offer half of your baby’s naps in the crib.
At 4 months old, your baby should be aiming for 4 naps per day. Try to offer at least 2 (or more) naps in the crib, with the rest on-the-go. Crib naps give your baby the chance to connect their sleep cycles and enjoy higher-quality rest during the day.

Step 3: Ditch the props.
Evaluate which sleep props are no longer working. Are you nursing, rocking, or bouncing to sleep, and finding it’s not cutting it anymore? That’s a sign your baby is ready to learn independent sleep habits. Identify any props that aren’t helping, and remove them from your routine entirely.

A common question:

“Should I Wait for the 4-Month Sleep Regression to End Before Sleep Training?”

Well, the 4-month sleep regression is not a storm that you wait to pass before you get to go outside and enjoy life again.

The 4-month sleep regression is a developmental milestone—your baby is transitioning to mature sleep cycles, which is a good thing! As outlined in the three steps above, your baby is now ready to start learning how to sleep independently, without relying on props or external help.

So, the answer is: yes, now is a great time to start sleep training! By teaching your baby these skills now, you’ll set them up for better, more restful sleep in the months to come.