The 4-Month Sleep Regression

The 4-Month Sleep Regression

Dec 30, 2021Guest Contributor

This is a guest blog post written by Umma Shekhani, founder and CEO of Two Baby Bears and Co and a mom of five little ones. She designed and created the award-winning  Swaddle Sleeves Sack to help provide a solution for babies that love to be swaddled, but are starting to learn how to roll. 


Sleep is one of the toughest parts of becoming a new parent. And teaching your baby how to fall asleep on their own as a baby is an important life skill that they aren't born knowing how to do. 

But the good news is that through educating yourself all about infant sleep and choosing the right products to support your child with safe sleep, you'll be as prepared as possible to conquer this challenging part of parenting. 

What is a sleep regression?

Around this time, your 4-month-old is undergoing a pretty infamous developmental leap.  (Keep in mind that every baby is unique, and this regression can occur somewhere around the 4-month mark, give or take a couple of weeks). 

During this time, your little one’s sleep cycles are maturing to become similar, yet shorter, to that of an adult. Which causes them to need to 'relearn' how to put themselves back to sleep. Meaning, your champion three-month-old sleeper is now waking up every two hours again! 

Like most "regressions" you hear about, this change in sleep development is actually a developmental “progression.” Your baby is undergoing tremendous brain development and is building the foundation for healthy toddler and childhood sleep. 

Infant Sleep Cycles

For the first 6-8 weeks of life, your newborn has what are called “immature” sleep cycles. What does this mean? It means that their circadian rhythm is still sorting itself out. They don't know the difference between day and night and their sleep is often all over the place. They may have a 3-hour nap followed by a 10-minute nap. Sleep is inconsistent, and it's frustrating to say the least. 

Newborns also experience deep stages of sleep. You may notice that your newborn sleeps anywhere...even in noisy and bright environments. However, as your infant approaches the 8-week mark, sleep environment and sleep routines become much more important when creating the best sleep environment for them.

A great way to maximize sleep during the first few months is to use a swaddle to ensure that your baby's sleep environment is as similar as possible to their life inside of their mother. 

And as your baby grows and transitions to new sleep stage, noises are more likely to wake your baby up during these lighter stages of sleep. White noise machines help to block out external noise so that your little one can stay asleep for longer stretches of time. 

Four Stages of Infant Sleep

As your baby hits the 4 month age, they are now experiencing more stages of sleep. Rather than transitioning between 2 stages of sleep (light and deep sleep), your baby is now experiencing a full 4 stages of sleep.

Let's go over them below:

  1. Stage 1 is a very light stage of sleep which is described as “Falling asleep” or “dozing off”. 
  2. Stage 2 is still a light stage of sleep where your body temperature starts to lower and prepare for deeper stages of sleep. 
  3. Stage 3 is deep and restorative.  In this stage, body tissues repair, the body’s immune system and energy levels are recharged. 
  4. Stage 4 is where we dream.  This stage is also referred to as REM sleep. This is where memories and sensory information is processed. 

Newborns spend more of their time in Stages 3 and 4 of sleep. Once the “regression” hits, they spend time in all 4 stages of sleep. These lighter stages of sleep are where they are more easily disturbed and babies rely on their sleep crutch to fall back asleep for another cycle through these stages. They are then woken up after the cycle completes itself and need to learn how to put themselves back to sleep to ensure longer stretches of rest. 

Handling Short Naps

If your once perfect little napper is now having short naps and waking up fussy, it may be as simple teaching them to go to sleep on their own without a "sleep crutch". 

A sleep crutch is anything that you use to put your baby to sleep. Most often this is a bottle/nursing, rocking or holding. If they are waking up after only one cycle of sleep and aren't able to put themselves through to the next, they may be looking for their "sleep crutch" to help them turn over. And if you're not there to do that, then they will wake up! 

Prior to this regression, you were able to survive by relying on these sleep crutches. You were able to rock your baby to sleep, put them in their crib, and walk away. As a newborn, they immediately fell into deep stages of sleep, but now, they are in lighter stages of sleep. And they may be able to notice when you lay them down and walk away.

So the cycle continues, you rock, nurse, bottle feed, or bounce your baby to sleep only for him to wake up once he is laid down. This easily turns into a fussy, overtired baby.  And a frustrated and exhausted parent. 

Addressing and transitioning away from "sleep crutches" is an important piece of graduating from the 4 month sleep regression, but we know it isn't easy. It can be a challenge to re-teach your baby how to fall asleep on their own, without a pacifier or being rocked, but trust us that if you stick to it and remain consistent, your baby is able to learn how to fall asleep on their own and stay asleep. And it will lead to longer stretches of sleep for you both and less frustration and fussiness during awake time. You can do it!  

Developmental Milestones

Most sleep regressions coincide with a newly learned skill or important milestone, such as rolling. Your little one is SO excited to practice their newfound skills that they want to practice All. The. Time.  Even in the middle of the night or when they are supposed to be napping!

While not all of these regressions can be avoided, my advice to you is to

  1. Take a deep breath
  2. Remind yourself that this is temporary
  3. Practice, practice, practice. The more often that they practice their newfound skills during awake time, the sooner they can master the skill and the novelty will wear off

How Long Will Sleep Regressions Last?

Unlike other regressions, the 4-month sleep regression is not necessarily temporary. Why? Because is it not just a phase, but rather the maturing of their sleep cycles. Sleep regressions look different for every baby and on average they last 2- 6 weeks. This may sound daunting, but fear not! 

With some sleep training, your little one can learn how to self soothe and fall asleep independently. Falling asleep independently is a skill your child will need for the rest of their lives! You are teaching them valuable skills that they will use forever.

Are you struggling with infant sleep? What's been the hardest part and what has helped you the most? Let other new parents know in the comments below. 


Umma Shekhani Swaddle Sleeves Umma Shekhani is the founder and CEO of Two Baby Bears and Co and a mom of five little ones. She designed and created the award-winning  Swaddle Sleeves Sack to help provide a solution for babies that love to be swaddled, but are starting to learn how to roll. Her unique sleep product allows your baby's arms to be free, yet still lightly weighted to muffle the startle reflex. Shop her products and follow Two Baby Bears on Instagram for more sleep tips.

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