I’ll never forget the night my eldest was exactly four months old. We’d just started to feel like we knew what we were doing with sleep—stretches were longer, bedtime was predictable, and for a brief moment, I dared to think, “Okay… maybe we’ve cracked it.” Then, out of nowhere, BOOM: back to waking every 45 minutes, fighting naps, and fussing at the very mention of bedtime. Sound familiar? Welcome to the infamous 4 month sleep regression.
What Is the 4 Month Sleep Regression Really Like?
If you’re going through it, I see you—bleary-eyed and clutching that third cup of coffee. The 4 month sleep regression feels like your baby has totally forgotten how to sleep. And honestly, you might start to wonder if it’s something you did (spoiler: it’s not!). For me, it set in overnight with both kids—suddenly, every nap and bedtime felt like trying to snuggle an angry hedgehog.
What’s Actually Happening in Their Little Brains?
Here’s what took me ages to understand: babies’ sleep changes for good at this stage. Up to now, their sleep cycle was more like a newborn (deep sleep, lots of sleepy cuddles). Around 4 months, they start cycling between light and deep sleep like adults—except they don’t know how to get themselves back to sleep when they wake up between cycles. It’s not your imagination!
The science backs it up: according to the AAP, this stage is caused by brain development, and it’s a permanent shift. Welcome to the real baby sleep routine.
Signs Your Baby Is Hitting the 4 Month Sleep Regression
Honestly, I missed the signs with my first until we were right in it. Some red flags:
- WAY more night wakings (like, every hour)
- Short, unpredictable naps (the dreaded 30-minute special)
- Fussier before sleep (hello, overtired monster)
- Suddenly struggles to fall asleep without you
Tip: If you’re wondering if something else is up (like illness or teething), check out this handy list of baby teething signs. Sometimes, it’s both!
How Long Does the 4 Month Sleep Regression Last?
Here’s the tough love: most babies take 2 to 6 weeks to settle into their new patterns. My youngest took three LONG weeks. Some nights felt endless, but things did get easier once we found our rhythm.
If you’re worried your baby might not settle, here’s a reassuring read on what’s typical in those early months: Baby 0-6 Months What to Expect.
So What Helps? Realistic Tips That Actually Work
Every baby is different, but there are things that made a massive difference for us:
1. Keep the Sleep Space Calm and Predictable
Babies are little pattern-seekers, so consistency is a lifesaver. Even when naps are total chaos, keep bedtime routines steady (bath, PJs, quiet snuggle, lights out). I used to hum the same lullaby every night—eventually, it became our sleepy cue.
2. Try Not to Rush In (Easier Said Than Done)
I used to leap up at every squawk, but sometimes, babies will resettle on their own if given a minute. Think of it as their first little lesson in dozing off solo. Obviously, still go if they’re upset (trust your gut!), but pausing for a few moments genuinely helped my second start to fall back asleep.
3. Let Go of Perfect Schedules for a Bit
During the regression, naps are a mess—it’s okay! Some days, I just wore my baby in a carrier and walked until she nodded off. Sleep is sleep, however you get it. Once the regression passes, you can gently guide them back to whatever routine you prefer.
4. Create the Right Sleep Environment
Think dark, cool, and quiet. Our magic temperature was about 22°C (72°F)—there’s real science to suggest babies sleep best here (NHS guidance). We used white noise to muffle sudden sounds. Soft night light so I could feed without turning on blinding bulbs.
5. Feed When Needed—It’s Normal
Regression means more night wakings, which sometimes means more night feeds. Their tummy is still tiny at this age (learn more about baby stomach size here). If you’re breastfeeding or bottle-feeding, don’t be surprised if those feeds seem endless again for a few weeks. Both of mine ramped up at night, then settled back down once the regression faded.
What About Gentle Sleep Strategies?
If you’re not into strict sleep training (I never was), there ARE gentle ways to help babies adjust. I relied a lot on these tips, and they’re especially helpful through sleep regressions:
- Gradually space out feeds and cuddles at night instead of dropping them cold turkey
- Try introducing a lovey or comfort item (if safe and age appropriate)
- Offer extra soothing at bedtime but step back when you can
For more ideas, the post on Gentle Newborn Sleep is full of realistic, no-pressure strategies.
When Should You Worry?
Worried that something’s off? Here are some signs to check in with your GP, health visitor, or paediatrician:
- Baby has a sudden fever, is refusing all feeds, or seems unusually irritable
- You notice any pauses in breathing (always get urgent help in this case)
- Baby isn’t gaining weight or is losing weight
Sometimes we just need reassurance that what we’re seeing is truly normal.
How to Survive (And Actually Sleep Again)
Here’s the truth: you will get through this. In our house, survival looked like taking short naps whenever I could, tag-teaming with my partner, and accepting help (even if just so I could shower). It helped to hear from other parents who had been through it too. If you’re struggling to understand why sleep gets so hard as a new parent, this post on why nights feel harder for new parents feels like a big virtual hug.
Lean on your community, drink the coffee, laugh about the chaos when you can—and know you’re doing an incredible job. This phase truly does pass.
Final Thoughts on the 4 Month Sleep Regression
There’s no magic fix for the 4 month sleep regression, but there is support—and a lot of solidarity from parents who get it. If you’re in the thick of it, give yourself some grace, trust your instincts, and go gentle on routines until things settle.
One day soon, you’ll wake up and realize the longest stretch of sleep you’ve had in weeks just happened. It really does get better, I promise.