How to Get a Baby to Sleep Longer Than 45 Minutes

(The 4-Month Sleep Regression Survival Guide)

Your baby used to sleep 3–4 hour stretches.

Now they’re up every 45 minutes like clockwork, screaming, and you’re losing your mind.

Welcome to the 4-month sleep regression — it’s real, it’s brutal, and it happens to almost everyone.

Here’s exactly what’s happening and the fixes that actually work (no cry-it-out required unless you want it).

What’s Actually Going On (It’s Not Your Fault)

Around 3–5 months, baby’s sleep cycles mature from newborn patterns to adult-like ones.

They now have light sleep phases every 45 minutes and have to learn to link cycles themselves.

Quick science: At 4 months the brain shifts from 50/50 REM/non-REM to 25/75, just like adults. Falling back asleep between cycles is a learned skill — that’s why the 45-minute wake-ups start.

(Source: Journal of Sleep Research, 2021)

“We thought we broke our baby. Turns out it’s biology. Wish someone had just said that.”

— Dad in r/sleeptrain

The Fixes That Actually Add Hours (Pick one or mix)

1. Perfect the bedtime routine (30–45 min before sleep) Bath → massage → PJs → feed → book → bed. Same order, every night.
2. Earlier bedtime (6:30–7:30 p.m. — yes, really) Overtired = more wake-ups.
3. Feed right before bed (the “tank-up” feed) Dream feed at 10 p.m. if needed.
4. White noise + blackout curtains (loud and dark = deeper sleep) Hatch Rest or $30 Dohm + $20 Amazon blackout panels.
5. Pause before rushing in (the 3-minute rule) Give them a chance to link cycles themselves.
6. Pick a gentle sleep-training method if you’re ready
   • Pick-Up-Put-Down
   • Chair Method
   • Ferber (check-ins) Most parents see 8–11 hour nights within 5–10 days.

Gear That Made a Difference for Parents

• Hatch Rest+ “Okay-to-wake light + sound machine in one. Saved us at 5 a.m. wake-ups.”
• SlumberPod (blackout tent over pack ’n play) “Turned any room pitch black. Naps went from 45 min to 2 hours.”
• Love to Dream transition sack “Arms-up swaddle with zip-off wings — perfect for the regression rollercoaster.”

Your 4-Month Regression Survival Checklist

• Bedtime 6:30–7:30 p.m.
• Feed right before sleep
• Loud white noise + total darkness
• Pause 3 minutes before going in
• Consistent routine every night
• Pick one sleep method and stick to it 2 weeks

You’ve got this.

It feels permanent, but it’s not. Most babies are sleeping 8–11 hours by 5–6 months with these tweaks.

One long stretch, one tired smile, one full night at a time. ❤️