Surviving the 4-month sleep regression

Somewhere between two and six months, every baby goes through a lasting shift in their sleep architecture. Pair that with the whirlwind of developmental changes happening around the four-month mark, and sleep can feel a little (or a lot) chaotic. This is what’s often called the “four-month sleep regression”—but knowing what’s going on can make it all feel way less daunting.

What is the four-month sleep regression?

To put it simply, the four-month sleep regression refers to challenging sleep symptoms that typically coincide with numerous developmental changes around four months of age. 

The two main changes that impact sleep at this time are:

• Fundamental change in sleep architecture: Instead of two primary sleep stages, REM-like and NREM-like, your baby now has four distinct sleep stages. There are now more opportunities for your baby to rouse and awaken between stages. Which is why we often see such a shift in their sleep. Some babies will wake fully and need support to get back to sleep. You might feel like you have a newborn again. Settling, re-settling and transferring to the crib may become harder because baby enters sleep via non-REM sleep versus REM sleep. This means your baby goes through a few sleep stages before they are fully asleep.

• Learning to roll: Not only is your baby inclined to practice their new gross motor skill at night, they have to adjust to belly sleep and sleeping without a swaddle. This can be a big transition for little ones.

Your baby may also need less sleep in a 24-hour cycle, be gaining more awareness during the day and/or be breastfeeding more due to the supply-and-demand relationship.

What’s going on with their sleep?

Newborns have two primary sleep states:

• Active Sleep (REM-like): During this stage, babies’ eyes might move, and they may twitch or jerk their limbs.

• Quiet Sleep (NREM-like): In this stage, babies are still and restful.

For adults and older babies, there are four distinct sleep stages.

• REM Sleep 

• NREM Sleep Stage 1: Light Sleep

• NREM Sleep Stage 2: Light Sleep

• NREM Sleep Stage 3: Deep Sleep

These sleep changes are signaling important neural developments, allowing your baby to continue growing, learning, and hitting milestones (yay!), but it also means their sleep patterns may shift, which can make the nights and days feel a little more challenging.

Four-month sleep regression telltale signs:

• Frequent night wakes 

• Needing more support to get to sleep and back to sleep throughout the night

• Naps shorten in duration

• Breathing changes: as they enter more mature sleep, their breathing will become slower, deeper, and more rhythmic, similar to adult sleep. This change is the result of their airway muscles relaxing and signifies a transition to more organized breathing.

Every baby responds differently to the sleep and developmental shifts around four months. Some breeze through with no disruptions, while others hit a rough patch. Your little one’s temperament and how they’ve historically settled to sleep will shape their experience.

Some will find it very difficult to settle after partial or full arousals from sleep and rely on external support to get back to sleep. Others will make the transition back into sleep seamlessly. There is no set amount of time that you may see disruptions. Some babies will gradually rely less on external support and begin sleeping longer stretches. Others will cling to this extra support and need you to make changes before they sleep better.

Tips to help you navigate the four-month sleep regression:

Quality Feeds:

Quality feeds are a driver of quality sleep. Focus on full feeds during the day and consider anchoring the morning feed at a regular time. Babies are great calorie counters so feed in a quiet setting if your baby is easily distracted.

Thoughtfully Respond to Nighttime Wakes:

Not every night waking is about hunger! Help your baby get back to sleep with alternative settling supports rather than introducing more nighttime feeds. You can try rubbing their back, rocking, and/or giving them a chance to put themselves back to sleep independently.

Update Wake Windows:

Update wake windows. Stop following a short nap with a short wake window. Use motion, baby-wearing or contact to help your baby get at least one solid nap each day. Aim for 1.75 to 2.25 hours between sleeps.

Introduce a Wind-Down Routine:

Consistency is key, so implement a calming set of steps before all naps and bedtime.

Sunlight Exposure:

Expose baby to sunlight first thing in the morning to help regulate circadian rhythm.

Stick to a Routine:

Be consistent with morning rise, the first nap of the day and the end of the last nap to allow for a predictable bedtime.

Transition to a Sleep Sack:

This is the time to ditch the swaddle and move to a sleep sack. This is also a great time to move from bassinet to crib so your baby has more room to wiggle and adjust through lighter phases of sleep.

Tummy Time:

Give your baby plenty of time on the floor to get their energy out. Regular tummy time during the day is vital for strengthening your baby’s muscles and supporting their physical development, along with practice rolling during the day and any skills that they might be trying to accomplish.

Remember to take care of yourself:

This season can be exhausting. In order to show up as the best parent you want to be, it's crucial to make sure your needs are met. 

Self-care looks different for everyone. For some, it may mean taking shifts with your partner so you can get more rest, or even taking turns sleeping in on weekends. 

You might need to ditch the housework, opt for grocery delivery, or treat yourself to takeout. 

Whatever helps lighten your load, make time for it. 

Be radically honest with yourself about how you're feeling, and check to see if you’re exhibiting any symptoms of sleep deprivation:

• Heightened stress response

• Increased likelihood of PPD and PPA

• Loss of interest in things you normally enjoy

• Feeling overwhelmed and unable to cope

• Weakened immune system

• Difficulty losing weight

These symptoms don't support a happy and healthy mother-baby dyad, and no mother can bear all of this while taking care of the baby's needs. If sleep becomes unsustainable, sleep training can be life-saving! You should never feel guilty for establishing a sleep routine that ensures the entire family gets quality rest.

You’re going to get through this! (albeit- with an extra matcha)

While the four-month sleep regression can feel daunting, it’s an important developmental milestone that signals your baby’s growth. By staying consistent with routines, observing your baby’s cues, and making decisions that benefit the whole family, you’ll be able to navigate sleep with ease.

If you’re frustrated with your baby’s sleep and not sure where to turn, check out my FREE Sleep Studio Resources HERE! 

If you want to learn about working together to sleep train your 4-5 month old baby, reach out HERE!

To better sleep,

Ella