4 Month Sleep Regression: Causes and What to Do?

Amber Lore

If you’ve started noticing some changes, you’re not alone! Around this age babies aren’t always able to fall asleep anywhere, anytime the way they did as newborns. Parents also frequently report shorter naps and an increase in night wakings. This is due to an exciting (though potentially exhausting) developmental change. 

Developmental changes at 3-4 months

By 3-4 months old, babies are able to produce enough melatonin, which allows them to adapt to a 24 hour cycle. While a newborn’s sleep is not strongly controlled by circadian rhythm (our internal “body clock” that helps controls sleep), that all starts to change at this age. Sleep begins to mature and babies start sleeping in different stages and cycles, similar to the sleep patterns of an adult. 

How this change can spark a “regression”

Once a baby starts to sleep in cycles of 60+ minutes long, they’ll have a brief period of wakening after each cycle. While this period of wakefulness can lead to new sleep challenges (we’ll get to that in a second), it’s actually a pretty cool built-in protective mechanism -- allowing the body to check in on one’s environment and make sure they’re safe throughout the night. 

It’s those brief awake periods that can cause a lot of disruptions to sleep and lead to the dreaded 4-month “regression.”  We put quotes around the word because we view it as somewhat of a misnomer. Changes in sleep are caused by a biological change in the way a child sleeps at this age rather than a regression.

This is how it typically plays out: A baby will fall asleep in their parent’s arms/swing/bouncy seat and then will be moved to the crib. Then, later, when the child wakes in between sleep cycles and the environment is different from the way they fell asleep at the beginning of the night, this can cause them to wake fully (rather than fall back to sleep on their own and onto the next sleep cycle). Once fully awake they’ll often want some help from their parent so that they can get back to sleep. Needless to say, this can be extremely disruptive to a family’s sleep if that happens repeatedly throughout the night.

Think of it this way - It would be like if you fell asleep with a pillow and when you woke up during the night, it had mysteriously vanished. You’d want that pillow back and might have a hard time returning to sleep without it. However, if your pillow had remained under your head, you’d be able to just roll over and fall back to sleep. 

What you can do:

We’re not bringing this up to alarm you, but rather to let you know that it’s the perfect time to take action! Sleep is critical for brain development and overall health and we don’t want anyone missing out on sleep if they don’t have to. Whether you’ve started to notice sleep changes or not, here’s what you can do to make the transition smooth:

  • Give baby an opportunity to fall asleep where they will spend most of the night

    One of the best ways to prevent babies from waking frequently at night is to help them learn to fall asleep at bedtime under the same conditions that will be present for the rest of the night. If your goal is for your baby to spend most of the night in their crib, then give them some practice falling asleep there. If they tend to fall asleep in your arms (or another sleep surface), you’ll want to give them the time and opportunity to adjust to falling asleep in the preferred sleep space.

  • Don’t rush in

    Babies can make a lot of noise in their sleep. If your child starts to stir in between cycles, don’t assume they immediately need your help. Many will fall back to sleep on their own after a few minutes if given the chance!

  • Sign Up for a full analysis and step-by-step plan

    Sleep issues can be complicated! Let our data scientists and sleep experts get to work on developing a program specifically designed with your family’s challenges and goals in mind.

You don’t need to be an ancient Greek philosopher to appreciate that change is the only constant in life -- especially when it comes to parenting. Luckily the team at Huckleberry has your back through all the sleep changes ahead: from dropping naps to sleep-space transitions and improving sleep in general. Let’s do this together! 

Related Topics: 4 Month Old Sleep Schedule And Development

*Huckleberry Premium was created to make sleep consultations for children more affordable for families. We take into consideration the uniqueness of every family's lifestyle as well as their sleep goals when working to create a successful sleep plan. If you are interested in more personalized analysis and guidance for your child, sign up for Huckleberry Premium.

About the Author:
Amber LoRe is a pediatric sleep consultant with Huckleberry. She's always considered herself an advocate for children - from early jobs in daycare to her work as a family law attorney. She's been helping families get more sleep since 2011 and never gets tired of hearing success stories from happy clients. Amber lives outside NYC with her husband, their two awesome children and their rescue pup.

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