The Four-Month Sleep Progression: Understanding and Navigating This Milestone
Somewhere around 3.5 to 4 months of age, your baby’s sleep undergoes a significant transformation. Sleep matures from being a constant state to a dynamic one, with distinct stages and cycles that are more like those of adults.
This change is often referred to as the four-month sleep progression (or regression), and while it’s a natural part of development, it can be challenging for both parents and babies. Understanding these changes and how to support your baby during this time is essential for healthy sleep habits.
The Two Sleep Stages of Newborns
Newborns sleep is simpler than that of older babies. They experience only two sleep stages:
Active Sleep: This is similar to REM (Rapid Eye Movement) sleep in adults and is a lighter sleep stage where babies may twitch, grimace, or even startle.
Quiet Sleep: Comparable to non-REM sleep, this is a deeper, more restful state.
Newborns cycle through these stages roughly every 50-60 minutes. As they grow, their sleep evolves to include additional stages.
The Four Sleep Stages That Develop Around 4 Months
By 4 months, your baby’s brain matures, and their sleep structure changes to include four distinct stages:
1. Stage 1 (NREM):
· Light sleep, characterized by drifting in and out of consciousness.
· Eye movements are slow and irregular.
2. Stage 2 (NREM):
· Deeper sleep, with increased brain wave activity and muscle relaxation.
· Sleep spindles and K-complexes appear on the EEG.
3. Stage 3 (NREM):
· Deepest sleep, with large, slow brain waves (delta waves).
· This stage is crucial for physical and mental restoration.
4. REM (Rapid Eye Movement):
· Dream sleep, characterized by rapid eye movements, increased brain activity, and temporary paralysis of the body.
· This stage is important for cognitive function, memory consolidation, and emotional regulation.
These stages cycle predictably, with each cycle lasting about 60-90 minutes at night and slightly shorter during naps. Understanding these sleep cycles helps you respond appropriately to your baby’s needs.
The Role of Sleep Cycles
At the end of each sleep cycle, babies experience brief awakenings. These awakenings are natural and protective, allowing them to check in with their environment. However, if their sleep environment or conditions differ from how they initially fell asleep, they may fully wake up and struggle to return to sleep.
Common Sleep Challenges at 4 Months
Sleep Associations: If your baby relies on being fed, rocked, or held in order to fall asleep, they may struggle to self-soothe during these awakenings.
Increased Night Wakings: As sleep cycles mature, it is natural that babies have more awakenings between these sleep cycles. Parents often interpret these awakenings as hunger and feed their baby, reinforcing the association between feeding and sleep.
Day-Night Calorie Imbalance: Because of the increase in night wakings, parents tend to add more night feedings. However, this can lead to babies consuming more calories at night and less during the day, perpetuating disrupted sleep patterns.
The Importance of the Sleep Environment
Creating a consistent and conducive sleep environment is crucial.
It becomes more important than ever that your baby falls asleep in the place where they will be sleeping on their own. This may take some time, but allowing them to fall asleep in their sleep space will help them navigate this biological change.
This is how it typically plays out: Your baby falls asleep in your arms or while feeding, then is moved to the crib. Later, when they wake up in between sleep cycles and their environment is different from the way they fell asleep, this causes them to wake fully (rather than fall back to sleep on their own and shift into the next sleep cycle).
Once they are fully awake, they will want everything put back in place according to how they fell asleep.
Think of it like this: you fall asleep with a pillow, but when you wake up during the night, it’s mysteriously vanished. You’d want that pillow back, and you might have a hard time falling back to sleep without it. However, if your pillow had remained under your head, you’d be able to just roll over and fall back to sleep.
If you know your baby has been able to sleep through the night for a certain length of time, assume that he/she is not hungry and can sleep for a minimum of that length of time without being fed.
In fact, when working with a family who is trying to get their baby to sleep better at night, I usually recommend no feedings before 12 midnight. In general, most babies can make it that long, and this helps them keep that portion of their night sleep consolidated, which is the most restorative sleep of the night.
For a 4-month-old, it is safe to assume that your baby could be hungry 3 hours after that midnight feeding. So, planning for another feeding at the next wakeup that occurs at least 3 hours later will give your baby what he needs. You always respond to needs, and if baby is hungry, then you respond.
Night sleep during the early morning hours is not as deep as the sleep that occurs before midnight, so it is easier for your baby’s hunger to interrupt their sleep at this time. Often, once your baby knows how to fall asleep on his own, he may sleep through those early morning feedings!
Tips for Navigating the Four-Month Sleep Progression
1. Assess the Sleep Environment: Make sure you have the basics in place – dark, DARK room, white noise to shield baby from environmental noises in the home and outside the window, and a cool room conducive for sleep.
2. When Baby Wakes, Don’t Assume They’re Hungry: If your baby has previously slept for longer stretches, it’s likely they can continue to do so. Most 4-month-olds can go a minimum of 6 hours before needing a feeding. If your baby can fall asleep at bedtime on their own, and fi you wait to feed your baby until the first wake-up after midnight, you may find that’s all you need to do to improve night sleep!
3. Prioritize Consolidated Night Sleep: Night sleep before midnight is the most restorative. Aim to keep this portion uninterrupted.
4. Adjust Daytime Feedings: Encourage full feedings during the day to ensure your baby gets the calories they need while awake.
5. Consider Gentle Sleep Learning: If sleep challenges persist, introducing gentle sleep training methods can help your baby develop self-soothing skills.
Supporting Research
· Stages of Sleep: What Happens in a Sleep Cycle
· Bedtime routines and objectively assessed sleep in infants
When to Seek Professional Help
If you’re struggling through this transition, consider reaching out for support. At Stargazer Sleep Consulting, we specialize in helping families navigate sleep changes with personalized, gentle strategies.
Contact us today to learn more about how we can support your family’s sleep journey!
