The 4-Month Regression: What's Happening & How to Survive It

Your baby was sleeping beautifully—maybe even giving you those glorious 4- to 5-hour stretches. You finally felt human again. And then, out of nowhere, everything falls apart. Suddenly, your once-great sleeper is waking every hour, fighting naps like it’s their job, and you’re wondering what on earth happened.

This is the 4-month regression.

Honestly, this one hits different because you thought you’d figured things out. The good news? There’s actually a reason for this chaos, and there are a few strategies to help you get through it.

You’re not alone in this—every parent and baby goes through it. And while this phase brings some permanent changes to how your baby sleeps, it won’t always feel this hard.

What Is the 4 Month Sleep Regression?

Here’s the thing. “Regression” is somewhat misleading. What’s really happening is a progression in how your baby’s brain processes sleep. Around 4 months, babies transition from those simple newborn sleep cycles to more complex, adult-like sleep patterns.

Before this shift, newborns cycle between just two sleep stages: Active (REM) sleep and Quiet (NREM) sleep. But now, your baby is learning to move through multiple stages of light and deep sleep—and they’re waking slightly between each cycle. The challenge? They haven’t figured out how to put themselves back to sleep when those brief wakings happen.

Unlike the other upcoming regressions (the 8-month, 12-month, and 18-month versions), this one represents a permanent change in sleep architecture. That might sound intimidating, but here’s the silver lining: addressing healthy sleep habits now can set the foundation for better sleep long-term.

“Keep in mind that any habits you create now while your baby is small will likely carry through for several more months, if not years,” notes Kristin Revere, sleep consultant, newborn care specialist, and founder of Gold Coast Doulas. “There’s nothing wrong with it as long as it’s working for everyone. And by everyone, I mean you, your partner, and your baby.”

When Does the 4 Month Sleep Regression Start?

Despite the name, this regression doesn’t always show up at exactly 4 months. It typically happens somewhere between 3 and 5 months. Some babies will hit it on the earlier end, while others don’t experience it until closer to 5 months. Both are completely normal.

Plus, this sleep shift often coincides with other major developmental leaps. Many parents notice their baby learning to roll, becoming more aware of their surroundings, and hitting other exciting milestones during the 4-month regression. No wonder they’re going through a little hiccup in their routine—so much is happening!

4 Month Sleep Regression Signs to Watch For

Wondering if you’re actually in the thick of the 4-month regression? Here are some telltale signs:

Your previously good sleeper is suddenly resisting sleep
Night wakings are creeping in every 1 to 2 hours
Naps have become wildly unpredictable (hello, 30-minute nap cycles)
Increased fussiness around sleep times
Needing more help to initially fall asleep than before
Changes in feeding patterns with more frequent night feeds
Difficulty falling back asleep after waking between sleep cycles

Is it the regression or something else?

Before assuming it’s a regression, it’s important to rule out other culprits, like illness, early teething, or growth spurt-related hunger. The key differentiator is that a regression typically affects all sleep—both naps and nighttime—not just one or the other. So if you’re seeing disruption across the board, you’re likely in regression territory.

How Long Does the 4 Month Sleep Regression Last?

The thick of it typically lasts 2 to 6 weeks, although every baby is different. Some families see improvement in as little as two weeks, while others navigate it for closer to eight. We’re not going to sugarcoat it—when you’re in the middle of it, even two weeks feels like an eternity.

Several factors can also affect how long this phase lasts, like whether your baby learns to connect sleep cycles more independently, the consistency of their sleep environment and routines, and their individual temperament (some babies are simply more adaptable than others).

But if sleep hasn’t improved after 6+ weeks, it may be time to evaluate the sleep habits that formed during the regression. The “waiting it out” approach works for some families, but not all—and that’s okay. This is where personalized support can make a real difference. A sleep consultant can help you figure out what’s going on and create a plan that works for you and your baby.

4 Month Old Wake Windows

Wake windows—the time your baby is awake between sleep periods—become especially important during the 4-month regression. At this age, most babies do best with wake windows of 1.5 to 2 hours. These windows typically lengthen throughout the day, with shorter ones in the morning and longer stretches before bedtime.

Wake windows matter so much right now because overtired babies actually have more trouble sleeping, not less—their tired bodies produce cortisol that makes settling even harder. On the flip side, undertired babies will fight sleep because they simply aren’t ready. So think of wake windows as your secret weapon during this phase.

To go along with wake windows, it’s also very helpful to know the signs that your baby is getting tired:

Staring off into space or zoning out
Rubbing eyes or ears
Fussiness that escalates quickly
Slightly darker tint around eyebrows
Yawning (though this can be a late sign)

“When your baby is in active playtime, it’s important to learn your baby’s sleep cues here,” says Kristin. “Notice and understand these cues because it’s your baby communicating with you. They are telling you they are starting to get tired, and you have a small window of time.”

Sample 4 Month Sleep Schedule

First things first—this is a framework, not a rigid schedule. Always follow your baby’s cues or ask for a personalized schedule from a sleep consultant. While every baby is different, here’s what a typical day might look like for a 4-month-old:

Morning wake-up around 7:00 AM
First nap approximately 1.5 to 2 hours after waking
Second nap mid-day, around noon
Third nap in the late afternoon around 3 PM
Possibly a fourth catnap if needed around 5:00 PM
Bedtime typically between 7:00 and 8:00 PM

Total daytime sleep usually falls between 3 and 5 hours spread across 3 to 4 naps, and the nighttime sleep goal is 10 to 12 hours (with feeds as needed). But at the end of the day, the “right” schedule is the one that works for your baby and your family. Tweak as needed!

Tips to Survive the 4 Month Sleep Regression

1. Optimize the sleep environment

Darkness matters more now that your baby is cycling through lighter sleep stages—blackout curtains can be helpful on super sunny days. Plus, a white noise machine during sleep can help bridge those sleep cycle transitions.

2. Create consistent routines + associations

There’s real power in predictable sleep times and a bedtime routine. And it doesn’t need to be elaborate. Simple and repeatable is the goal. Think of routines as your baby’s signal that sleep is coming. For example, try keeping sleep times consistent each day, using the same lullaby, or even a routine bath before bedtime.

3. Maintain sufficient daytime feedings

If your baby isn’t getting enough calories during daylight hours, they may start making up for it overnight with frequent wakings. Keep offering feeds every 2 to 3.5 hours during the day, following your baby’s hunger cues.

What NOT to do

Don’t panic and try everything at once. Consistency matters more than finding the perfect solution.
Don’t compare your baby to others. Every baby handles this transition differently. Comparing will do more harm than good.
Don’t blame yourself. This regression isn’t caused by anything you did or didn’t do.
Please, don’t ignore your own needs. Ask for help, tag-team with your partner when possible, and take a break when you can.

How to Know When You Need Help

Sometimes riding it out works. But there are signs it might be time for some professional support:

Exhaustion is affecting your mental health or ability to function
Sleep hasn’t improved after 6+ weeks
You’re feeling overwhelmed and don’t know where to start
The whole family is struggling, and you need a clear plan

If you’re in the thick of it and need personalized guidance, Gold Coast Doulas offers virtual and in-person sleep consultations with certified sleep consultants who can create a plan tailored to your family’s needs and values. And because consultations are available virtually, families anywhere can get support.

“You need to do what’s best for you, your baby, your partner, and your growing family,” Kristin shares. “Trust your instincts. Ask questions. Believe in yourself and know that you’re going to be awesome at this parenting gig.”

Bottom line? The 4-month regression is hard, but it’s temporary. Your baby is developing exactly as they should, and better sleep is absolutely possible—whether through time, small adjustments, or professional support. You’re doing an incredible job navigating something really challenging. And it won’t be like this forever.

Kristin Revere, MM, CED, NCS, is a certified birth and postpartum doula and the founder of Gold Coast Doulas in Grand Rapids, Michigan. She is also the co-host of Ask the Doulas Podcast and co-author of Supported: Your Guide to Birth and Baby.