May 12, 2020

All You Need to Know About the Four Month Regression

Babies, Newborns

Did the mere title of this post make the hairs on the back of your neck stand straight up? Those who have heard of the four month regression dread those words.

My now toddler was a pretty good sleeper as a newborn. However, around that four month mark is when her sleep went downhill, and I joke that “it lasted until she was 10 months old.”

It did not, in fact, last until she was 10 months old, but her dependent sleep habits that grew even more dependent at four months lasted that long.

No matter how many times she would wake in the night, I would immediately nurse her and then burp/rock her to ensure she was fast asleep, and then put her down. She often stayed asleep upon put down, but I occasionally had to repeat the same process a few times until she stayed asleep.

That then became our pattern and remained so until she turned 10 months old and we had had enough.

So in this post, I am going to share with you what I wish I had known about the four month sleep regression a few years ago, including:

  • What the four month sleep regression is and why it happens
  • How to know if your baby is in the four month regression
  • How to help your baby through the four month regression

So what is the four month sleep regression?

It’s an actual, physical change happening to your baby’s sleep. Newborn babies’ sleep is underdeveloped, meaning they only have two sleep cycles. Around four months of age (it might be a little before or a little after), babies’ sleep starts transitioning into developed, adult-like cycles, having four stages of sleep per sleep cycle. (If you want to dig a little more deeply into these different stages of sleep, head here!)

Newborns don’t spend as much time in lighter stages of sleep as older babies, toddlers, and adults do, so it’s quite the adjustment!

What does the four month sleep regression look like?

For most babies, the four month regression looks like an uptick in night wakings and potentially shorter naps, because as I mentioned above, newborns are not used to spend as much time in lighter stages of sleep – it’s almost like they keep “falling out” of sleep.

The reason many families think this regression “lasts forever” is because we start and/or continue a lot of prop-dependent habits to try to maintain some semblance of sanity and sleep in our households (I’ve been there!!), and as a result we teach our child to be even more prop-dependent.

The exciting news is, four month olds don’t simply hit a regression, they also hit a “progression”; four months is when babies are able to learn to self-soothe, meaning this is also where we can officially start sleep training!

How to help your baby during the four month regression while also encouraging good sleep skills?

Transition out of the Swaddle

If your little one is still in a swaddle, it’s time to transition out. Movement is such a big piece of learning to self-soothe, so not only is swaddling unsafe once your baby is able to roll over, it’s preventing him from learning to use his body to self-soothe.

Check the Sleep Environment

A newborn’s REM sleep is light, however these two new stages of sleep (stage 1 and 2) are much lighter, making it even easier for your baby to wake up. Make sure your child’s sleep environment is as dark as absolutely possible, and use white noise! We don’t want any environmental factors waking baby before necessary.

Have a Consistent Bedtime Routine

Establish and follow the same bedtime routine each night! This will help your baby’s mind and body prepare for sleep.


If your child wakes in the night, wait 10 minutes before responding, as he may simply fall back to sleep. If he hasn’t calmed in that time, go in and soothe him.

If it’s been at least three hours since his last feeding, feed him, however do your best to keep him awake so he’s aware that he’s eating, and he’s aware that he’s being laid back in bed. (Side note: a four month old should only need to eat one or two times per night. A general rule of thumb is that he shouldn’t need a night feeding before midnight.)

Hold to Personal Best

Hold your baby to his “personal best”! If he’s only been waking up one or two times to feed during the night and is now waking four times, he should not all of a sudden need to eat four times.


Although the four month regression is technically unavoidable, as all babies’ sleep physically changes, it is possible to greatly minimize the impact it has on your baby. This is why I love working with newborn families, because although you can’t “sleep train” a newborn, you can absolutely teach him sleep skills from the start, which will greatly decrease the impact of the four month regression, and help you avoid formal sleep training down the road.

With Grace,


Four month regression