
Understanding the 4-Month Sleep Regression
The 4-month sleep regression is one of the first big transitions you might experience with your baby’s sleep. It typically occurs between 3-5 months of age and can feel like it comes out of nowhere. One day, your baby may be sleeping in long stretches at night and going down easily for naps, and the next, they’re waking every couple of hours, fighting sleep, or taking 20-minute naps.
This period, though challenging, marks an important milestone in your baby’s development. Their sleep patterns are transitioning from newborn sleep cycles to more mature, adult-like cycles. As your baby grows, their circadian rhythm (or internal body clock) begins to develop, and their sleep becomes more structured. While this is a permanent change in how your baby sleeps, the chaos it causes doesn’t have to last forever.
What Is the 4-Month Sleep Regression?

During this regression, your baby’s sleep becomes more complex as they shift from short newborn cycles to the more intricate stages of adult sleep. This includes light sleep, deep sleep, and REM sleep. These changes can cause your baby to wake more often during lighter sleep stages, and if they don’t yet have independent sleep skills, they may need help resettling.
Milestones like rolling, grabbing, or babbling often occur around this age, further disrupting sleep. Combined with a more alert and curious baby, it’s no wonder this phase can feel overwhelming. But with patience and a few strategic changes, you can help your baby adjust.
Common Signs of the 4-Month Sleep Regression
You might notice:
More frequent wake-ups at night
Shorter naps (20–40 minutes)
Fussiness or increased irritability
Difficulty settling at bedtime
Distracted daytime feedings, leading to more frequent night feedings
These behaviors are typical, but understanding why they happen can make all the difference in addressing them.
Why Do Sleep Associations Become Challenging?
Before this stage, you may have been able to rock, nurse, or use a pacifier to quickly soothe your baby to sleep. However, as your baby’s sleep patterns mature, they spend more time in lighter stages of sleep. If they wake up and their sleep environment doesn’t match how they fell asleep (e.g., they were rocked but now find themselves in the crib), they’ll likely cry for help.
This is a great time to gently teach your baby independent sleep skills. Babies between 3-6 months are incredibly adaptable, making this a golden window for introducing changes that will set the stage for long-term sleep success.
Tips to Help Your Baby Through the 4-Month Sleep Regression
Create a consistent bedtime and nap routine to signal it’s time for sleep - grab my free guide here for creating your own bedtime routine.
Darken the sleep environment with blackout curtains to reduce stimulation.
Stick to age-appropriate wake windows to avoid overtiredness.
Transition away from sleep props like rocking, feeding, or replacing the pacifier to sleep.
Practice crib sleeping during naps to help your baby adjust to their sleep environment.
Gradually stop swaddling if your baby is ready to transition to a sleep sack.
For a detailed wake window and sleep schedule tailored to each age group, grab my FREE Wake Window and Sleep Schedule Guide!
Resources to Support You Through the Regression
Unfortunately , the sleep cycle changes that happen at this age are permanent and so there is no end date when it comes to the 4 month regression.
But the good news… you don’t have to wait to for them to “end” before making changes to your baby’s sleep.
If you’re still struggling with multiple wake-ups, short naps, or bedtime resistance, you don’t have to figure it out alone. My DIY Dreams Package is designed to help you establish a personalized sleep training plan. You’ll learn how to guide your baby toward 11–12 hours of independent night sleep, improve naps, and set up a daily routine that works for your family.
Need more personalized help? My Sweet Dreams Package provides daily support for two weeks to tackle both overnight and nap challenges. Together, we’ll create a plan tailored to your baby’s unique needs. Let’s work together to bring restful nights and peaceful days back to your home!
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