My 4-month-old baby isn't sleeping anymore, is it sleep regression?

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

In short: Yes, this looks exactly like the 4-month sleep regression. It's one of the toughest phases, but it's temporary and typically lasts between 2 and 6 weeks.

Why it happens

At 4 months, your baby's brain goes through a fundamental change in sleep cycles:

• Sleep cycles mature — they shift from newborn cycles to cycles similar to an adult's
• Between each cycle (every 45-90 minutes), your baby wakes briefly and needs help falling back asleep
• It's not a step backward — it's progress in brain development

What can help

• White noise — mimics the womb environment and helps connect sleep cycles
• Complete darkness — blackout curtains promote melatonin production
• Consistent bedtime routine — bath, feeding, lullaby, always in the same order
• Put baby to bed early — an overtired baby sleeps worse, not better
• Skin-to-skin contact — calms your baby and reduces cortisol

When to contact your pediatrician

• If your baby seems sick (not just restless)
• If they refuse feeds during the day
• If there's no improvement after 8 weeks

What other moms say

"It lasted 3 weeks for us. The worst part was everyone telling me to let her cry it out. I didn't, and she got through this phase on her own. Trust your instinct."

Remember: this phase will pass. You're doing an incredible job.

This information does not replace medical advice.