Understanding The Dreaded Four Month Sleep Regression

Cara Dumaplin, Founder

“He was sleeping great, but suddenly he started waking up every hour. It’s harder now than when he was a newborn.” Oh this story is so common when I’m speaking to sleep deprived parents. “It all started at about three to four months. I’m at a loss of what to do.”

The dreaded “four month sleep regression” has struck. Let me see if I can simplify it for you and truly help you understand what is happening with your little one’s sleep.

What is the Four Month Sleep Regression?

At about 3-5 months of age, our babies move from the newborn phases of sleep into more adult-like sleep stages.

The Science Behind it: 

These sleep stages string together into “sleep cycles.” These cycles last 60 -120 minutes during the night. The end of each cycle has a mini “wake-up.” (Yes, you and I “wake up” five to eight times per night. This is our body’s way to check that we are, indeed, safe. You and I have gotten so good at putting ourselves back to sleep after these mini wake-ups, we don’t even know that we were briefly awake.)

Great! How Does This Apply To My Baby?

Well, at 3-5 months of age, he will go through these sleep cycles and at the end of 60, 90, or 120 minutes each night, his body will slightly awaken him. He will check in with his environment, making sure that everything is okay and his surroundings are unchanged. See the chart below to understand what this looks like over the course of the night:

For those who have taken my newborn class, “Will I Ever Sleep Again,” you have been gradually working on setting your baby down to fall asleep on his own at bedtime. You have also been helping him slowly transition between sleep cycles (Tip 7 in the newborn class). Now, this is when it really pays off. If your baby put himself to sleep in his own crib/bassinet, he hits this new sleep cycle, awakens slightly, and looks around. He knows his bassinet and knows how to put himself back to sleep. Some babies sail smoothly through this regression because of these skills. 

Oh, if only it were that easy for all babies!! If you are struggling, please know you’ve done nothing wrong. Even the best of sleepers can struggle during this time. And, Taking Cara Babies has help for you: “Navigating Months 3 & 4” is a 50-page ebook that helps walk you through each and every step of this transitional phase. 

But what if your baby is rocked, fed, walked, or bounced to sleep? 

She, too, will enter this stage of new sleep cycles. Let’s play out that scenario: She fell asleep in mom’s arms and then is set down in the bassinet when she’s fast asleep. After about 60, 90, or 120 minutes, she will awaken and check in with her environment. Guess what her little body says during the check in: “Hey, this isn’t right! My surroundings are different. I was in Mom’s arms when I fell asleep. Where am I now? In this horrible, awful bassinet!  Waaaaaa! Mama, come get me.”  (Can you blame her? What if you fell asleep in your bed and awoke a few hours later in a different bed? Wouldn’t you freak out and cry?) Our bodies expect our surroundings to be unchanged during these wake-ups.

 So, what do Mamas do when our babies cry in the night? Well, we assume they must be hungry, so we feed them and they fall back to sleep. Now, they’ve entered this new stage of sleep cycles, so one to two hours later, they are awake again. We convince ourselves that they must be having a growth spurt. We offer another feeding. Then 1-2 hours later… awake again! A few nights of this, and now, their little bodies become accustomed to this frequent waking. They will need to be rocked or fed back to sleep because this is how they fell asleep at bedtime.  This is the beginning of sleepless nights and labeled “the 4 month sleep regression.”

Add In Some New Developmental Changes:

During months three and four our babies become aware of the big world around them.  During the day, they suddenly notice big brother playing with toys, the dog running around the room, the light from our cell phone flashing, and all sorts of other exciting happenings in the environment that before was just background noise. All of these things are WAAAAAY more interesting than eating. So our babies naturally get shortened, smaller feedings as they become more distracted by this exciting, big world.

Couple that with all the extra feedings baby received last night, and there’s really no reason to eat well today. Right?

So, guess what happens tonight? He awakens every 1-2 hours in accordance to these new sleep cycles, but he’s genuinely hungry because he didn’t eat much during the day. This creates a cycle of night wakings with multiple feedings due to poor (or not-so-great) daytime feedings.

Make sense as to why nights turn into nightmares?

If you’re struggling with this problem of getting a large majority of the calories in at night, this is called “reverse cycling.” “Navigating Months 3 & 4” will give you step by step instructions to gently prevent or correct reverse cycling.

So, What Can Be Done?  

  1. Take the newborn class: “Will I Ever Sleep Again” while you’re expecting or in the first 12 weeks of your baby’s life. I’m telling you…this REALLY helps. Laying a strong sleep foundation PRIOR to hitting this stage will give you tools before you are struggling.
  1. Implement the tips learned in this class. Truly work on setting your baby down while awake. (No crying involved, by the way!)  No, I’m not saying that you can’t ever hold your baby while she’s sleeping. I promise you can! Watch the class. I’ll explain how to create this balance. 
  1. Recognize the change in sleep cycles at 3 to 4 months of age. Prepare your mind that it will happen, but don’t let it scare you!
  2. Put your baby down awake at bedtime. If you’re thinking “yeah, right, not my baby,” “Navigating Months 3 & 4” will help you slowly work toward this goal by giving you practical steps.
  1. When your baby awakens at the top of a natural sleep cycle, give him a few minutes to put himself back to sleep. A bit of fussing or grunting may be heard. That’s okay! Just pause. Give him a few minutes to put himself to sleep. If you don’t know how to do this gently, “Navigating Months 3 & 4” explains exactly how to help your baby learn how to fall back to sleep more independently.
  1. Maintain adequate feedings during the day. Continue offering feedings every 2.5-3.5 hours during the day according to your baby’s hunger cues.
  1. If everything falls apart and you recognize that the “4 month sleep regression” is wreaking havoc on your nights, please know Navigating Months 3 & 4 was written for you. This 50-page ebook is not sleep training, but rather clear and practical steps to help you as your baby is facing huge developmental strides. It’s all about helping you prevent huge sleep crutches that can last for months. It’s about making baby steps during a time that can be so rough for many families. 


Bonus Tip: By all means, do not unswaddle for nighttime sleeping unless your baby is showing signs of rolling. (If showing signs of rolling: check out Merlin’s Magic Sleep Suit.) If you haven’t read the blog post about transitioning out of the swaddle, you can read that HERE.

  1. If by 5 months of age your baby isn’t sleeping through the night, Taking Cara Babies can help. “The ABC’s of Sleep” is an online class for you. This class gives you a step-by-step plan to help your baby overcome the issues that make your nights unbearable. It’s a 14 night plan to 10-12 hour nights in the crib. It will cover bedtime, night wakings, night weaning, early morning wakings, and naps through the first two years of life… through regressions, teething, illnesses, and any setbacks too. We will slowly wean the night feedings and get your baby sleeping 10-12 hours EACH and EVERY night. 

Your nights don’t have to be exhausting anymore.

hey there!

I'm Cara.

I’m a mom of four, neonatal nurse, and wife of a pediatrician. My passion is teaching parents how to help their babies sleep with the science of a nurse and the heart of a mama so they can reclaim the joy of parenthood.

I'm Cara.

I’m a mom of four, neonatal nurse, and wife of a pediatrician. My passion is teaching parents how to help their babies sleep with the science of a nurse and the heart of a mama so they can reclaim the joy of parenthood.