If you have a baby, you’ve likely been warned about the “four month sleep regression.” You may be experiencing it right now with your baby or you may be wondering when it’s going to happen. 

Maybe your baby was a great sleeper and now they’re waking up every hour on the hour or they’re back to taking extremely short naps. If you feel like your baby is taking steps backwards with their sleep and they’re between 3-5 months, chances are, they’re going through the four month sleep regression. This post will explain what it is, why it happens, and what you can do to support your baby through it. 

If you have a newborn and you want to be as prepared as possible for the four month sleep regression BEFORE it happens, our Newborn Class can help you and your baby get better sleep from day one! Many parents don’t even recognize the four month sleep regression happening if they’ve implemented all the tips from our class!

When does the four month sleep regression happen?

The “four month sleep regression” happens at different times for different babies, but typically happens between 3-5 months. 

What is the four month sleep regression?

We think it's a little misleading to describe what happens around 4 months as a sleep “regression.” It might feel like your baby is moving backwards, but their sleep is developing exactly how it should. They’re changing and growing, and that’s actually a great thing! 

Sleep is a cycle with different stages. Between 3-5 months your baby transitions into more developed + more complex sleep cycles. 

Newborns experience only two sleep stages: deep sleep and light sleep.

As those sleep patterns change, they come to have 4 stages of sleep, and cycle more frequently in and out of light and deep sleep. This can mean they will wake up more often throughout the night, sometimes as often as every 45-120 minutes.

When your baby was a newborn, it was likely possible for you to rock or feed them to sleep and lay them down without waking them up. This is because when they fell asleep, they went straight into deep sleep.

Once their sleep cycles develop, they no longer go straight into deep sleep. Their sleep is much lighter initially and they’re easily woken up.

Did you know that no one (adults or babies) ever sleep through the night completely? Adults and babies 3+ months old cycle through these different stages of sleep throughout the night. The entire cycle lasts between 60-120 minutes. When we complete one of these cycles, we all briefly wake up. 

When adults complete a sleep cycle and experience this brief awakening, we might open our eyes and look around to see that everything is how it should be, but then we almost always fall right back to sleep. We may not even realize we woke up because it happens so quickly. 

Babies do this, too. They experience these same brief awakenings multiple times a night. They check on their surroundings to make sure they’re safe and everything is the same as it was when they fell asleep. 

If a baby doesn’t know how to fall asleep on their own (if they depend on someone or something else to help them fall asleep - nursing, bottles, rocking etc) they will fully wake up between sleep cycles and won’t know how to put themselves back to sleep on their own.

It’s very unsettling to them if they wake up and their environment is different than when they fell asleep (i.e. they originally fell asleep in your arms but wake up alone in their crib). 

Imagine if you fell asleep in one room of your home but then woke up somewhere else. It would be pretty upsetting!  

That’s what happens to your baby each time they transition through a sleep cycle (every 60 - 120 minutes). They experience the normal brief awakening, but they find themselves in a different environment or under different circumstances than they originally fell asleep in and they don’t know how to smoothly put themselves back to sleep without help. 

Your baby is learning new skills

Another factor that makes the Four Month Sleep Regression tough is the fact that your baby is going through a developmental milestone. Most likely, you baby is learning how to roll! Your little one’s brain is working extra hard during this time as they master their newfound skill of rolling over. Giving your baby plenty of time to practice rolling during wake time is key!

What can we do to support our babies during the 4 month sleep regression?

• Keep their sleep environment dark

Our sleep is regulated by our circadian rhythms (or internal clocks) which tell us when we are supposed to be awake and when we are supposed to sleep. Light plays a huge role on our internal clocks. Exposure to light stimulates parts of the brain that control hormones (like melatonin production), body temperature and other functions that play a role in making us feel sleepy or wide-awake.

When your baby was a newborn, they could sleep anywhere and everywhere. You probably noticed that bright lights and noise didn’t bother them much at all. Now that your baby is a little older, not only are their sleep cycles developing, but their internal clocks (circadian rhythms) are mature. Light and darkness now plays a huge role in your baby’s sleep. 

You can support their sleep and get their internal clocks set appropriately by having them sleep in a very dark environment during naps and nighttime sleep. When we say dark, we mean DARK. Black out their rooms, no exceptions. Such a little thing can make a massive difference in their length and quality of sleep. 

• Make sure your baby is on the appropriate schedule during the day

  • You can help set your baby up for successful nighttime sleep if you set their days up appropriately. Getting their wake windows right (the amount of time they can handle being awake) and making sure they’re getting the right amount of daytime sleep is crucial for nighttime sleep. 

  • Click HERE to get your child’s perfect daily schedule!

Click HERE to get your child’s perfect daily schedule! 

• Make sure your baby is getting full feedings during the day

Aside from your baby experiencing new, complex sleep cycles, they’re also becoming more aware of their surroundings and learning new skills (like how to roll, etc). 

You might notice your baby is too distracted to eat during the day because they’re too busy watching everything going on around them. This is when it’s super important to make sure they get enough to eat during the day. If not, they’ll have to make up for those lost calories during the night which will add to the night time wakings. 

To help them get enough to eat during the day, try feeding them in a very calm environment with as few distractions as possible. You may need to go into a dark, quiet room away from the rest of the family. A sound machine might help drown out noisy distractions as well. 

Make sure you’re feeding your baby at appropriate intervals. If they’re eating too frequently, they will be more easily distracted and they won’t take a full feeding because they aren’t truly hungry yet.  

• Begin helping your baby learn to fall asleep on their own without sleep props or external help 

Helping your baby develop the skills to fall asleep on their own is such a gift to them. It’s a lifelong skill that they need in order to grow and thrive physically, mentally, and emotionally. Aside from sleep having a direct effect on a baby’s happiness and emotions, research has shown that sleep impacts a baby’s cognitive abilities, growth, and every area of their development. (see our full post about the importance of sleep and it’s benefits for babies HERE). 

If your baby is fed, rocked, held etc to sleep, they’re going to need those things every single time they wake up between sleep cycles. If they’re never given the opportunity to learn the skills necessary to fall asleep on their own, they’ll always need that external help. 

We understand how daunting it is to help your baby learn to fall asleep independently. The amount of advice and opinions coming at parents is paralyzing. That’s why we’ve created our online classes and offer 1:1 consulting. If you need a plan, schedule a free discovery call HERE or work 1:1 with us and we’ll create a Personalized Sleep Plan for your child!

If you have a newborn and you want to be as prepared as possible for the four month sleep regression BEFORE it happens, our Newborn Class can help you and your baby get better sleep from day one! Many parents don’t even recognize the four month sleep regression happening if they’ve implemented all the tips from our class!

The classes and package options are created specifically for you. At the Goodnight House, our hearts are to teach you how to help your baby sleep better and experience more rest, peace, and joy in parenthood.