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The 4 Month Sleep "Regression"

As a sleep consultant, I hear the term “regression” used a lot. Your baby doesn’t sleep well for a few nights and many parents are quick to start using the “R” word. A simple Google search will reveal many regressions, including a 6 month regression, 8 month regression, 9 month regression, teething regressions, growth spurt regressions…I could go on and on.

Others parents aren’t quite as likely to believe that each interruption to their baby’s sleep is a “regression”.

Whatever your take is on sleep regressions, everyone can agree on the 4 month sleep regression. It does exist. And it’s permanent. The best way to explain this regression to you is to start with a few general sleep facts, so please bear with me.

Sleep is a bit more complicated than simply sleeping or not sleeping. We sleep in cycles that have a number of different stages.

  • Stage 1: This is when you feel yourself drifting off, but don’t think you’ve actually fallen asleep. If someone would nudge you, you’d insist “I wasn’t sleeping!”

  • Stage 2: This is where people tend to realize, once woken up, that they actually were sleeping. For anyone taking a power nap, this is as deep as you want to go, otherwise you’re going to wake up groggy.

  • Stage 3: This stage is deep and regenerative. Also known as “slow wave” sleep, this is where the body starts repairing and rejuvenating the immune system, muscle tissue, energy stores, and where it sparks growth and development.

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

Once we’ve gone through all of the stages, we either wake up or come close to waking up, and then start over again until the alarm goes off.

Newborn babies only have 2 stages of sleep; Stage 3 and 4 (REM). They spend about 50% of their sleep in each stage. This is why your newborn baby is either completely zonked out (not even a toddler throwing a tantrum will wake her) or she is moving around and grunting so much that you are convinced she is awake but when you go to pick her up, her eyes are still closed!

Around 3-4 months, a baby’s sleep is reorganized. Their REM sleep is reduced to 25% of their sleep and they add in stages 1 and 2. Now they have 4 stages of sleep, just like we do. With more time now spent in lighter stages of sleep, babies are much more likely to wake up.

By the way, waking up is completely natural. We all wake up 3-5 times per night, even as adults! Now you may be thinking, “Not me, I can sleep straight through the night without waking (before I had a newborn of course)."

We are often not even aware that we were awake at night. When we have a brief waking, our body quickly recognizes “I’m still in my bed, it’s nighttime, there is no danger, I can go back to sleep”. And we do. When morning comes we don’t even remember those brief times we were awake.

A four months old, baby is going to handle those brief wakings a bit differently. A more likely scenario for a four month old is to wake in the night and think “OK, last thing I remember, I was with my mom, eating dinner, I was being rocked and sang to!” Baby is now completely confused and doesn’t know what to do. Her only way to express these feelings is to cry! This is where the “regression” begins.

It’s a pretty simple if you think about it. Baby has been nursed to sleep since birth, she doesn’t know how to fall asleep any other way. Now every time she wakes (which will be more often with the lighter stages of sleep), she will want to be nursed so she can fall back asleep.

Now begin the nights of your baby waking every hour or so.

The hard news I need to break to you is this: This new pattern is permanent. Your baby will have 4 sleep cycles for the rest of her life. This is going to become the new normal.

The fact is, the dreaded Four Month Sleep Regression is not a regression at all! A regression is defined as “reversion to an earlier mental or behavioral level,” and that’s actually the opposite of what your baby is experiencing. This would be much more aptly titled the “Four Month Sleep Progression”. It may be one of the very first signs of your baby “growing up”! (Cue the waterworks...)

So if this is permanent, what can you do to help your little one adjust?

Here are a few suggestions:

  • Blackout the room. Babies are not afraid of the dark. In fact, they are very responsive to light. Even the smallest amount of daylight can disrupt their sleep (during the night as well as naps).

  • Try a sound machine. Environmental noises are more likely to wake baby now that she is sleeping more lightly.

  • Implement a routine. These are very important! Over time, it will start to cue your baby’s brain that it’s time to sleep.

  • Watch the awake time. At four months, your baby can only handle about 1.5-2 hours awake at a time. An overtired baby will struggle to fall asleep and sleep well!

  • Early bedtime. Put your baby to bed between 7-8pm.

Finally, lay baby down awake. I understand that this may sound crazy at this point (especially if your baby has only ever gone to sleep with some amount of help), but it’s the only way to teach your baby to sleep independently and the only way your baby will start consolidating her night sleep.

I realize that is a bit blunt, but I prefer not to beat around the bush. That is the key right there.

In case you were wondering, this doesn’t mean you can’t feed your baby at night! My suggestion for night wakings is to start with a reasonable minimum. Your baby should be able to go 3-4 hours without a feed. If she wakes up and it has been 3 hours, go ahead and feed her! (Trying to keep her awake.) If it’s only been 1 hour, then wait 10 minutes, go in and check on her to offer comfort (but no feed).

There are going to be regressions, actual regressions, later on for your little one. Traveling, illness, cutting teeth, all of these things can cause your little one to have a few bad nights in a row. But when it comes to the four month “progression,” I’m happy to report that this is a one-time thing! Once you’re through this, your baby will have officially moved into the sleep cycles that she’ll essentially be following for the rest of their life.

By taking the opportunity now to teach your baby the skills she needs to string her new sleep cycles together you are giving her the gift of consolidated sleep and the opportunity to master the first skill of many that you will teach her down the road.

Some babies will catch on fast and others will struggle a bit to learn independent sleep. Personally, I had one fast learner and two that struggled. (I hope your odds are better than mine!)

If you find that your baby is struggling and would like someone to walk with you through the process, giving you a step by step plan to follow that is customized for YOUR baby, then please reach out. I would love to chat with you about what that looks like and let you discern if it’s the right move for your family.

My last piece of advice is this. Don’t wait to do something. Most of my clients tell me, “I wish I would have done this sooner.”


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