4th Month Sleep Regression

You may have heard parents talk about the 4-month sleep regression like it’s a storm you need to survive - and in many homes, it really does feel like something suddenly changes.
Just when sleep was starting to make a little sense… your baby’s patterns shift.

Let’s talk about why this happens, what’s normal, and gentle ways to support your little one (and yourself) through it.

What’s Actually Happening at 4 Months?

At around 3½ - 5 months, your baby’s sleep matures.

Their brain begins to develop adult-like sleep cycles, moving between:

• Light sleep

• Deep sleep

• REM (dream) sleep

This means your baby no longer “drifts” in and out of long stretches of sleep. Instead, they now wake briefly between cycles - just like adults do.

The difference is:
Adults know how to settle back to sleep. Babies are still learning that skill.

So if your baby relies on: Rocking, Feeding, Holding, Motion, Co-sleeping contact. …they may now need that every time they wake.

This is not a step backward. This is development.

Common Signs of the 4-Month Regression

You might notice:

• More night wakings

• Shorter naps (30 - 45 minutes)

• Restless or light sleep

• Increased feeding overnight

• Fussiness during naps or bedtime

• Difficulty transitioning from arms to crib/moses basket

It can feel sudden - but it’s normal and expected.

Why It Feels Hard for Parents. You’re suddenly:

• More tired

• Second-guessing what changed

• Wondering if something’s wrong

Nothing is wrong. Your baby is learning how to shift through new sleep cycles. And learning takes support - not pressure.

How to Gently Support Your Baby Through This Stage

1. Focus on Wake Windows

Proper timing reduces overtiredness, which makes sleep much easier.

Typical wake windows at 4 months:
75 - 120 minutes (start with the shorter end if baby seems tired quickly)

2. Create a Simple Bedtime Routine: 3 - 5 minutes is enough-

• Dim lights

• Fresh diaper

• Sleep sack

• Short lullaby / rocking / feeding

• Into bed calm, not fully asleep (when possible)

Consistency builds predictability → predictability builds safety.

3. Start Introduce “Sleep Soothing Cues”

These help baby settle with your support, not only motion or feeding.

Examples:

• Hand resting on chest

• Gentle shushing

• Rhythmic patting

• Humming

These cues become anchors your baby learns to trust.

4. Support, Don’t Replace, Their Needs

If baby is upset - hold them, soothe them, comfort them.

This isn’t about letting them “figure it out alone.”

It’s about slowly reducing how much effort you provide over time - not reducing connection.

How Long Does the Regression Last?

Most sleep shifts last: 2 - 6 weeks

But the important thing to know is: Your baby does not go “back” to newborn sleep. They are moving forward into more mature sleep patterns. Your gentle support now helps them build skills they’ll use for months and years.

If You’re Feeling Exhausted, Please Know:

You didn’t cause this.
Your baby is not “fighting sleep.”
You are not doing anything wrong.

You’re in a developmental milestone - not a problem that needs fixing.

And you’re doing beautifully, even on the tired days.