The 4-month sleep regression: why it sucks and what to do

Congratulations! You’ve made it four months in.

You’ve figured out your baby’s sleepy cues, your arms are a little buffer from all the rocking, and you’re finally sleeping in stretches that feel almost human (I hope!)

Then suddenly…

Waking every hour.

Nap refusal.

Screaming at bedtime like it’s a personal betrayal.

Welcome to the 4-month sleep regression aka: the moment your baby stops sleeping like a newborn and starts sleeping like… a baby... with opinions.

What is the 4-month sleep regression?

Around 3.5 to 5 months, your baby’s brain goes through a massive upgrade. Like your phone, it looks the same but it doesn't work the same and it's time to figure out what's new.

Their sleep cycles become more like ours. Read: lighter stages, more frequent transitions, and lots more chances to wake up and go “uh, where am I?”

Basically, they now:

• Wake more between sleep cycles

• Notice when you’re gone

• Need help learning how to settle back to sleep

It’s not a glitch. It’s a developmental leap. But yes, it still totally sucks.

Is this permanent?

Yes and no.

The regression part is temporary, but the new sleep pattern is here to stay.

So if your baby suddenly needs rocking, feeding, or bouncing back to sleep every 45 minutes… they’re not being difficult. They’re adjusting. And you’ll need to adjust with them.

What to do (that actually helps):

1. Dial up the routine

Predictability is your friend right now.

Same wind-down. Same nap space. Same sleepy cues. Babies thrive on “this means sleep is coming.”

2. Try putting them down drowsy… but awake-ish

This isn’t sleep training. It’s gentle exposure. Letting them practice falling asleep a little on their own builds the skill they’ll need to link sleep cycles. If you want to find a technique for how to do this based on what your little one currently likes, that's where Ask Yawn can help you make a personalised plan... right now if you need it.

3. Feed if it helps; there’s no shame game

Yes, they may genuinely be hungrier. It’s a big time for growth.

But if they’re snacking every hour and not feeding well during the day, we may need to stretch things out a bit.

4. Use contact naps or motion naps strategically

Overtired babies sleep worse. If naps are a mess, pop them in the carrier or pram to sneak in a longer stretch. It’s not a bad habit, it’s a lifeline. In fact, the more ways your baby can fall asleep, the better. One single, deep association (like only feeding to sleep) is way harder to change than having a few up your sleeve.

5. Zoom out. This is a phase. Really.

Most babies settle back into a new rhythm within a few weeks.You’re not doing anything wrong. This isn’t your fault. And no, you haven’t “created a rod for your back.”

TL;DR

Your baby’s brain just levelled up. Their sleep got worse because it got smarter.

You don’t need to fix it, just support them through it. And support yourself too.

If you need help deciding what’s a normal phase vs. what might need a tweak, Ask Yawn.

We’ll look at your baby’s age, nap pattern, routine, and what’s actually going on and give you a plan that fits. We're here to help if you need it.

You’ve got this. Even if your baby definitely doesn’t right now.