The 4-Month Sleep Regression: Why It Feels So Hard (and How to Get Through It)
If you’re reading this at 3 AM with a wide-awake baby in your arms, let me say this first: you are not alone. The 4-month sleep regression has a reputation for being one of the toughest stages in early parenthood—and for good reason.
Just when you thought you’d finally found a rhythm, your baby suddenly starts waking every hour, fighting naps, and refusing to stay asleep without help. It’s exhausting, disheartening, and honestly… a little confusing.
What’s Actually Happening?
Around 4 months, your baby’s sleep undergoes a huge developmental shift. Until now, their sleep cycles were simpler, allowing them to drift more easily between stages of sleep. But at this point, their brain matures and their sleep starts to look more like an adult’s—with lighter and deeper phases.
That’s the good news: it means your baby is developing exactly as they should. The hard part? They now wake more often between cycles and often need you to help them get back to sleep.
Signs of the 4-month regression include:
More frequent night wakings (sometimes every 1–2 hours)
Shorter naps
Trouble settling without lots of help
Increased fussiness during the day
Why This Regression Is Different
Here’s the thing most parents aren’t told: while other regressions eventually fade and sleep returns to “normal,” the 4-month sleep regression is permanent in one sense.
After this point, your baby’s sleep will not go back to how it was before. Their new, mature sleep cycles are here to stay. But that doesn’t mean you’re doomed to years of sleepless nights. It just means your baby is entering a new stage where healthy sleep habits and routines matter more than ever.
How Long Does It Last?
The most intense part usually lasts 2–6 weeks, but how long it feels depends a lot on your baby’s temperament—and on how you respond. Some babies adjust fairly quickly, while others may need a little more guidance to learn how to link their sleep cycles.
What Can You Do?
💤 Stick to a routine. Bedtime routines are your best friend. Repeating the same simple steps every night helps signal to your baby that sleep is coming.
💤 Encourage self-settling (little by little). If you always rock or feed to sleep, your baby may expect the same each time they wake. Try putting them down drowsy but awake when you can—practice makes progress.
💤 Watch those wake windows. At this age, babies can usually only handle 1.5–2 hours of awake time before they need to sleep again. Catching them before they’re overtired makes settling much easier.
💤 Offer comfort, but keep it sustainable. Responding to your baby’s needs is important, but try to avoid introducing new sleep habits you don’t want to continue long-term (like constant rocking all night).
💤 Give yourself grace. Some nights, survival mode is all you can manage—and that’s okay. Let the laundry sit, grab naps when you can, and lean on support if it’s available.
Final Thoughts
The 4-month sleep regression is tough, but it’s also a sign of progress. Your baby’s brain and body are growing in incredible ways, and this transition is part of that journey.
Sleep after 4 months won’t go back to the way it was—but it will move forward. With time, consistency, and patience (with both your baby and yourself), you’ll get through this phase and find a new rhythm.
Until then, know this: you’re not failing, you’re not alone, and you are doing an amazing job. 💛
Need Extra Help?
Daddy’s Lullaby is a leading sleep consultant based in the UK. If you are having issues with your little one’s sleep, have a look at my one-to-one sleep coaching plans.
And if it feels like you’ve tried everything and nothing has worked—don’t worry. That’s exactly where we step in. We’ll fix it.
