My 4-month-old baby doesn't sleep through the night anymore, what should I do?

Sleep Regression at 4 Months — You're Not Doing Anything Wrong 💙

In short: Yes, this looks exactly like the 4-month sleep regression. It usually lasts 2-6 weeks and is a sign of healthy brain development in your baby.

Why does it happen?

In the 4th month, your baby's sleep cycles change dramatically:

• Sleep cycles become like an adult's — alternating between light and deep sleep
• Between cycles (every 45-90 minutes) your baby wakes briefly
• Your baby still doesn't know how to fall back asleep on their own — they need your help
• This is a sign of normal development, not a problem

What helps?

• White noise — helps your baby transition between sleep cycles
• Dark room — use blackout curtains
• Consistent routine — bath, feeding, song, the same every night
• Put them to bed early — overtired babies sleep worse
• Patience — this period is temporary

What do other moms say?

"It lasted 3 weeks for us. Everyone kept telling me 'just let them cry a little.' I didn't, and it sorted itself out. The patience really is worth it."

"My mother-in-law kept saying 'give them cow's milk' but the doctor said breast milk only until 6 months. I trusted the doctor and made the right choice."

When should you see a doctor?

• If your baby seems sick (fever, vomiting) — not just fussy
• If they refuse food during the day
• If it continues for more than 8 weeks

This information does not replace medical advice.