If your 12-16 week old was finally sleeping longer stretches while you were breathing a sigh of relief and suddenly they are waking every two hours, there is a reason!
What Is the 4 Month Sleep Regression?
The 4 month sleep regression is a developmental milestone when your baby’s sleep cycle matures and begins to resemble that of an adult. Newborn sleep cycles have 2 stages while adult ones have 4. This means that while your newborn was easily able to go from light to deep sleep (hence being able to sleep easily in noisy environments and easily be able to be transferred), they are now entering lighter stages of sleep. This means they are waking up more fully as they are coming out of their cycles, which as you might guess, are about 2 hours long at night.
However, this period is not actually a true regression but rather a progression! Your baby is hitting a new developmental milestone that is directly related to sleep.
A lot of parents are also completely caught off guard because this progression is misnamed: most babies actually hit it when they are technically 3 months old!
Signs of the 4 Month Sleep Regression
Common symptoms include:
- Waking more often at night
- Short, inconsistent naps
- Trouble falling asleep at bedtime
- Increased fussiness or crankiness during the day
- Seeming tired but fighting sleep
Why Does It Happen?
At around 3.5 months, your baby’s brain is undergoing big changes. This is why when those sleep cycles start maturing, they are also often more fussy and making big developmental strides overall. I call it the official graduation from the newborn stage. This is where independent sleep can actually prevent and resolve this progression overall. If your baby doesn’t know how to transition between these cycles, they may wake up more often and need help falling back asleep. This means, if your baby is using feeding, rocking etc. to fall asleep in the first place, they will need these things repeated after coming out of their sleep cycles.
Other contributing factors:
- Growth spurts
- Increased awareness of surroundings
- Changes in feeding routines. When babies hit their progression, they often start feeding more frequently at night, reinforcing less feeding during the day. This can lead to reverse cycling.
How to Help Your Baby (and Yourself) Through It
1. Practice Consistent Sleep Routines
A soothing bedtime routine can signal to your baby that it’s time to wind down. Use the same sequence of events to give you baby the cue that sleep time is coming. As well, this age often comes with the need for an earlier bedtime. If your baby seems to be hitting the witching hour again and are super fussy before their later bedtime, it’s time to move it backwards! Bedtime should be somewhere between 7 and 8:00 p.m and babies are ready for an 11 hour night.
2. Encourage Independent Sleep Skills
Try placing your baby down awake. This helps them learn how to fall asleep on their own—so they’re more likely to resettle when they wake between cycles. This can be done through sleep training or through using a soothing ladder. The more you can reduce your intervention for when your baby falls asleep, the more likely they will be able to connect their own sleep cycles. Babies this age are ready for sleep training if you are!
3. Keep a Sleep-Friendly Environment
Make sure your baby’s room is cool, dark, and quiet. Use white noise and blackout curtains to create a consistent, calming sleep space. Light at this age can signal their brain to wake up more fully, especially in the early morning when sleep pressure is low.
4. Feed When Needed But Not Too Much
Hunger can still be a reason for night waking at this age. However, I highly recommend not feeding more frequently than before the regression hit to prevent reverse cycling. Follow your baby’s baseline. If they were going through the night with 1-2 night feedings, stick to this as reverse cycling will reinforce genuine hunger wakings. Most babies this age don’t need more than 2 night feedings with 1 being average. Feeding more frequently is probably more habit rather than hunger.
5. Optimize Your Daytime Routine
When a baby’s sleep cycle’s mature, it also often brings about an increase in alertness. Reevaluate if your baby’s daytime routine is appropriate. I find many babies need to take fewer naps and be up longer in between to help build sufficient sleep pressure for the night. Somewhere between 3 and 4 naps with about 3.5 hours of day sleep. An under tired baby will have a much harder time settling at night and connecting their sleep cycles.
When to Call a Baby Sleep Consultant
If the sleep regression feels overwhelming, or your baby is still struggling with sleep weeks after it begins, it might be time to reach out. As a certified baby sleep consultant based in Vancouver and working virtually with families worldwide, I offer personalized support to guide you through regressions, routines, and everything in between. For some babies, unless their habits improve and they learn how to fall asleep independently, this regression never seems to resolve fully. I can’t tell you how many clients have told me that their baby slept long stretches as a newborn and they could just never get back to that after the 4 month sleep regression hit.
Together, we’ll create a plan that suits your baby’s unique needs—so everyone in your home can start getting better rest.
👉 Click here to contact me and book your free discovery call today. Let’s get your little one (and you) sleeping soundly again.