As a Certified Pediatric Sleep Consultant, one of the most common questions I am asked, aside from the obvious “How do I get my baby to sleep?” is “Is there an [insert X month] sleep regression?”. 


Google tells you there’s a regression for just about every age. But I’m here to tell you: there is only one true sleep regression. It’s real, and it’s permanent.


And it happens between your baby’s third and fourth month of life.


That’s right, between 3 and 4 months of life your baby’s brain undergoes a massive change in the way they sleep, as they shift from newborn sleep to the way they will sleep for the rest of their life.


The Four-Month Regression can also be a double doozie because not only do you have the biological shift in your baby’s sleep cycles but developmental milestones (like learning how to roll over!) can also cause these temporary sleep disturbances.


Now if you’re in the thick of this you probably don’t need me to tell you that this regression is a real thing. And if you haven’t hit this marker yet, you’re might be feeling a little nervous.


But, today I’m going to shed some light on what’s actually happening during this permanent shift in your baby’s sleep. I’m also going to give you a few ways you can survive this transition and come out on the other side with a sleeping baby!


So, what is the Four-Month Sleep Regression?


The Four-Month Sleep Regression is the only true sleep regression. What do I mean by that? Well, throughout your child’s life, they will go through phases that naturally interrupt their steady sleep habits. Around 12-20 weeks of age, you may notice that your baby, who was sleeping pretty well, will start struggling with sleep. Your little one may have trouble falling asleep and staying asleep. Naptime may be shorter. You may not be able to put them down awake. They may be crankier than normal due to lack of quality sleep.


The good news is that this regression is the only true sleep regression and I hate to be the bearer of bad news, it’s permanent. But as your baby develops the sleep skills they need, they will begin to sleep well again. 


So why does this happen at around the four-month mark? Well, your child is reaching a pretty important developmental milestone. Babies are born with only two phases of sleep: deep, regenerative sleep and REM (rapid eye movement) sleep. As they grow, they begin to develop the rest of the sleep stages that we all experience for the rest of our lives.


These sleep stages are:


Stage 1 – During the stage, you feel tired and begin to drift off. However, you aren’t completely asleep and are probably aware of your surroundings.

Stage 2 – This is considered the first “true sleep” stage. Often we don’t realize we are in this stage until we wake up. Typically, when you take a quick nap you stay in this stage.

Stage 3 – Deep and regenerative sleep. Some people also refer to this as “slow-wave” sleep. During this stage, your body starts repairing and rejuvenating the immune system, muscle tissue, and energy stores, and sparks growth and development.

Stage 4 – REM (rapid eye movement) sleep. This is where the brain starts to kick in and consolidates information and memories from the day before. It’s also the stage where we do most of our dreaming. 


What does this have to do with my baby’s sleep?


With the shift to a 4-stage sleep cycle, babies are now spending more time is lighter stages of sleep. And when infants begin to incorporate these lighter stages of sleep, there is much more potential for them to be woken more easily from environmental noises (such as dogs barking, loud vehicles, the doorbell, etc.) and as well as their natural biology which brings them closer to the surface during these light stages of sleep.


As adults, we also “come to the surface of sleep” and this brief awakening is one that we don’t remember the next morning, as long as certain comforting truths are in place: we are still in our beds, it is still dark outside, and we have hours to sleep until morning. These transitions between sleep cycles are so brief and benign, that we have no conscious memory of them when we wake the next day.


Infants also experience similar sleep patterns and “come to the surface” of sleep just as often as adults. 


So why is my once good sleeper now waking so frequently?


Let’s say you have nursed, rocked, cuddled, or patted your little one to sleep then placed them down in their crib peacefully to continue their sleep. When they wake, even briefly, between sleep cycles, chances are they realize you are no longer nursing, rocking, cuddling, or patting them and they realize that they are not where they were or who they were with when they fell asleep. 


They are in a vastly different situation from the one they are used to falling asleep in and it’s confusing and startling, so much so this causes a full-blown wake-up rather than a seamless transition into their next sleep cycles. 


The other issue at this age is that babies are quickly becoming more cognitively aware of their surroundings, meaning that infants who rely on assistance to fall asleep (nursing, rocking, patting, bouncing, etc.) are more likely to protest when this assistance is absent during the night. They have learned or perceive they need those very specific circumstances created to be able to fall asleep.


Until now, you may have been sailing through the sleep world, rocking your baby to sleep, and your baby was sleeping great! But if your little one believes they need certain circumstances to fall asleep, these developmental changes are going to cause some major problems in the sleep realm. 


What can you do to help your little one through the Four-Month Regression?


The Four-Month Regression isn’t all that bad. In fact, it’s a great opportunity! Your baby now has a more mature biological clock and is capable of sleeping longer stretches because they can go longer between feeds! And they can now follow a more appropriate sleep-wake pattern. The possibilities are endless!


There are a few easy and practical strategies we recommend to our Sleep at Last families that are tried and tested ways to make it through this sleep regression. These suggestions will help you support healthy sleep habits so that you can help your child will move through this regression with ease, begin sleeping better sooner, and continue to sleep well for the rest of their lives.

  • Keep it Dark

Your child’s sleep environment should be as dark as possible. Sunlight sends signals to your child’s brain that it is time to wake up, so this can cause them to wake up earlier than they need to or have trouble falling asleep. If your child’s windows allow sunlight to come in, try these DIY tips


Of course, if DIY just isn’t your thing, I highly recommend Blackout EZ Window Covers. Tried and true, these are the best. And as a sleep consultant, I have tried a ton of different blackout methods. They go on the inside of the window so they do not damage anything. The way they adhere is very similar to 3M velcro strips. They have standard sizes but you can also customize to the size and shape you need. Plus they are super fast and easy to set up! I can definitely testify that they are 100% worth the investment.

  • Keep it Quiet

When your baby is in a lighter sleep phase, noise can easily wake them up. It can be especially hard to keep your home quiet during the daytime, when you can’t predict the timing of that Amazon package delivery or when your husband will drop every utensil you own in the kitchen. But in general, do what you can to keep your home quiet. You can also use a white noise machine to drown out any background noise that can’t be avoided.

  • Have a Steady Bedtime Routine

It’s never too early to establish a solid bedtime routine. The ideal routine consists of four to five steps and does not end with a feed. Instead, feed your baby during the beginning of the routine, including a bath, a few songs and stories, and a PJ change. The whole process should take 20-30 minutes and end with putting your baby down in their crib still awake. This routine should be easy to repeat night after night, and bedtime should be around 7 or 8 PM each night.

  • Avoid Using Sleep Props

When your child is struggling to sleep, many parents are tempted to do anything that they feel will help their child rest. This can include allowing your child to sleep on you, co-sleeping, feeding to sleep, and other sleep props. I would suggest avoiding any of these habits, as they can actually prevent your child from sleeping well in the long run. Instead, take this opportunity to support independent sleep habits that will set your child up for successful sleep (without your help) for the rest of their lives.


How long should the Four-Month Regression last?

The short answer is forever. But by ensuring your baby has healthy sleep habits, you are setting her up for long-term success. Teaching your baby the skill of independent sleep can be the trickiest but most important part because this is not a regression that “goes away”. Again, the changes occurring at 4 months are a permanent change to how your baby sleeps.


Teaching your baby the skill of independent sleep, prevents them from thinking that they always need someone or something else to fall asleep. You don’t want to be stuck in a vicious cycle where you have to go into your baby’s room all night to recreate the situation that got them to sleep in the first place. We want you and your baby to sleep soundly, all night, every night.


This last part, the teaching healthy sleep habits part, is not just something you want to “wing”. When teaching your baby the skill of independent sleep, you want to make sure you have a plan that you are comfortable with and confident carrying out in a consistent way in fairness to your baby. Inconsistency leads to confusion, confusion leads to crying, overwhelm, and frustration, and then no one will be getting any sleep.


If you’ve already hit the 4-month mark and are still struggling to get a good night’s sleep, I know a girl! I would be happy to chat with your family about your sleep struggles and see if the Four-Month Regression is truly the cause. I offer a FREE no-obligation Sleep Evaluation Call where you can learn how private sleep coaching may be the solution your family needs!