Settling into a predictable nap and sleep schedule with your baby feels like a dream come true. For many new parents, you may notice that just when you feel comfortable with your baby’s nighttime sleep routine, seemingly out of nowhere, your infant starts waking in the middle of the night fussy and cranky. 

Commonly referred to as the 4-month sleep regression, it is very common for your baby to experience a disruption in their sleep around the ages of 3 and 4 months old. In this article, we’re discussing the science behind your baby’s 4-month sleep regression and providing you with information to help you navigate this period of restless, sleepless nights. 

For more help with sleep problems or concerns, be sure to download the Kinedu app to watch live and on-demand classes about baby sleep and get individual guidance from experts.

What Causes The 4 Month Sleep Regression?

Sleep regressions are very common occurrences during the first year of your child’s life. They often occur right before or during a period of profound developmental growth. While your baby is learning and developing new skills, this process can leave them feeling anxious to practice them, frustrated, and not wanting to sleep at all. 

It is the lack of sleep that comes as a result of these behavioral changes that leads to fussiness, crying, and irritability that is associated with a baby going through a sleep regression. The good news is, sleep regressions do not last forever, and the more you learn about them, the more you can help your baby move through them. 

To understand why the 4-month sleep regression happens, it is important to know what developmental changes your 4-month-old is experiencing. 

Developmental Changes at 4 Months

There are some important developmental changes that can cause your baby’s sleep regression. These include both neurological developments, physical milestones, and cognitive developments. 

Neurologically, the sleep centers in your baby’s brain are maturing and changing permanently. Their circadian rhythm and homeostatic sleep drive are developing and beginning to influence their sleep patterns

Your 4-month-old baby is also learning new physical skills. At this age, one of the biggest 4-month-old milestones is learning to roll or flip over. This new skill is exciting for both you and your baby, and their desire to master this skill can impact their willingness to nap or sleep at night. 

In addition, your baby is also experiencing some major cognitive progressions as well. At 4 months old, your baby is becoming aware of the world around them in many different ways. They are beginning to notice things like temperature changes, changes in lighting, and increasingly aware of their attachment to you as their caregiver. 

All of these exciting new changes in your baby can cause some noticeable changes to their sleep patterns and overall behavior. 

What Are The Symptoms of a Sleep Regression?

When it comes to identifying the 4-month sleep regression in your baby, you will likely know that something is happening already. If your 3 or 4-month-old baby has had a consistent sleep experience and schedule that has abruptly stopped, it is safe to assume that you have reached the sleep regression phase. 

Some of the most common symptoms of sleep regressions are:

  • Your baby is waking up more frequently during her normal sleeping times.
  • Reduced amount of total sleep. 
  • Fussy or crying when waking up.
  • Your baby has trouble falling asleep at nap or bedtimes.
  • You notice your baby is more aware of thier surroundings and distracted by them,
  • During awake time, your baby is busy working on new physical milestones like rolling over

Once you recognize that your child is going through a 4-month sleep regression, you will probably want to know how long does the 4-month sleep regression last and how you can help your baby transition through it. 

Because the 4-month sleep regression is the first one you will face as a new parent, it may seem like it will never end. However, your baby will progress and develop through this period in about 2-6 weeks. As with all developmental changes, every baby will be different and will develop on their own timeline. 

During this phase, there are some things you can do to make it easier on both you and your baby. 

How Can I Help My Baby During The 4 Month Sleep Regression?

It can feel impossible to think clearly when you and your baby are not getting enough sleep. You probably feel like you’ve tried everything to no avail to help your baby sleep. Here are some tips to help you and your baby get more rest during a sleep regression. 

1. Control The Sleep Environment

Your baby is becoming increasingly more aware of their surroundings. Environmental factors like darkness and temperature can impact your baby’s ability to fall asleep or stay asleep.

The ideal temperature for sleep is 70°F/21°C. Keep this temperature in mind when dressing your baby for bed and setting your thermostat. Ideally, you want to keep a darkness level of 10 for nap and sleep times during the 4-month sleep regression. 

Eliminate all distractions and stimulants from your baby’s crib when it is time for sleep. Your infant’s new fascination with their surroundings will entice them to fight the urge to fall asleep. 

2. Follow The Science of Sleep

Around the ages of 3 and 4 months, your baby’s brain is developing its circadian rhythm. This process is directly influencing your infant’s sleep patterns. One of the ways you can help your baby’s body develop this rhythm is by adjusting their light exposure to simulate day and night. 

Exposing your baby to brighter lights and sunlight in the morning and during the daytime will help their neurological system recognize wake times. In the afternoon, slowly start lowering the amount of light exposure in increments as it approaches the evening. This simulation of light and dark assists in the development of the circadian rhythm. 

3. Maintain A Consistent Wake Time Limit

As your baby is developing new skills and interacting with the world around them in new ways, it is easy to want to allow them more time to be awake between naps. This is especially true during the 4-month sleep regression because your baby will want to stay up longer practicing their new skills. 

Between the ages of 3 and 4 months, recommended sleep and wake times haven’t changed much. At 3 months old, your baby still requires 14-17 hours of  sleep a day, and by 4 months, a total of 12-15 hours. On average, 10 of these hours will be nighttime sleep hours. 

If your baby is getting less sleep than they need, it is important to manage their wake time appropriately. During this time in their development, the recommended amount of wake time is no longer than 90 minutes. Making sure your baby is getting enough rest can help prevent the fussiness and crankiness that comes as a result of sleep deprivation during a sleep regression. 

4. Stay Calm and Be Patient

As hard as it may be in the middle of the night, after missing hours of sleep, staying calm is important. When you are with your baby, staying calm helps to soothe them and enforces a calming and stress-free environment. 

Even when you find yourself asking how long the 4-month sleep regression can last, or it feels like it’s been going on forever, remember that it is a short time in your baby’s development, and you will both be through it soon enough. 

If you need more help during the 4-month sleep regression, be sure to download Kinedu to get individual guidance from experts in early childhood development.