My 4-month-old baby doesn't sleep at night anymore, is it sleep regression?

4-Month Sleep Regression — You're Not Doing Anything Wrong 💙

In a nutshell: Yes, this is the famous 4-month sleep regression. It's one of the toughest phases, but it's temporary — it typically lasts 2 to 6 weeks.

Why this happens

Around 4 months, your baby's brain goes through a huge change in how they sleep:

• Sleep cycles mature — they start alternating between light and deep sleep, just like adults
• Between cycles (every 45-90 minutes), your baby wakes briefly — and needs help falling back asleep
• This is a sign of healthy development, not a problem
• Your baby hasn't "forgotten" how to sleep — they're learning to sleep in a new way

What can help

• White noise — mimics the womb environment and helps with the transition between cycles
• Darken the room — melatonin production needs darkness
• Consistent sleep routine — bath, feeding, lullaby, always in the same order
• Move bedtime earlier — an overtired baby sleeps worse, not better
• Cuddles and comfort — your baby needs you, and that's not "spoiling" them

When to talk to your pediatrician

• If your baby seems sick (not just restless)
• If they refuse to feed during the day
• If things don't improve after 8 weeks

What other moms say

"It was 3 weeks of chaos. I cried along with my son at 3 in the morning. But it passed. And on the other side came that beautiful smile that made it all worth it."

You're doing an amazing job, even when it doesn't feel like it. 💛

This information does not replace medical advice.