When little ones struggle with sleep, making sure they have independent sleep skills is the first thing we do. If they rely upon something to fall asleep, they can have the best routine in the world but they are probably still going to struggle to sleep well.  

To understand why your baby sleeps the way they do, it’s really helpful to understand the stages of sleep we all experience. Many people view sleep as simply an on-or-off state: either you’re asleep, or you’re not. However, sleep is actually a cycle consisting of five distinct stages that we go through multiple times each night. 

Stage 1 is the light, drifting-off phase, where you feel like you’re almost asleep but aren’t fully settled yet. Most people, if woken during this stage, often don’t realise they were sleeping at all. 

Stage 2 is when true sleep begins. People generally recognise they were actually sleeping after waking up from this stage. 

Stage 3/4 is deep, restorative sleep, often called “slow-wave sleep,” where your body repairs itself, restores energy, and stimulates growth and development. 

Stage 5 is REM (Rapid Eye Movement) sleep. This is when the brain becomes active, processing memories and experiences from the day. It’s also when we do most of our dreaming. 

After cycling through these stages, we either wake up or come close to waking, and the cycle restarts until morning. While this pattern is common for both children and adults, newborns experience sleep in a very different way. 

Newborn sleep and the four month “regression”

Newborns only have two stages of sleep: REM (dream) and deep sleep.

Typically, between 12-16 weeks, your baby undergoes a transition into sleep cycles. And this is what is typically referred to as the “four-month sleep regression”. While it can feel very much like a regression if you’ve had a newborn that has slept really well until this point, it’s actually a huge developmental leap in their sleep. Once your baby has made this shift, they’ll follow a more predictable sleep pattern for the rest of their life. 

At this point their REM sleep, which initially made up 50% of their sleep, drops to around 25% to accommodate the introduction of Stage 1 and Stage 2. This means your baby is experiencing sleep cycles more similar to those of an adult, though their cycle only lasts about 30-60 minutes, compared to an adult’s 90-minute cycle. 

This shift means your baby is spending more time in lighter sleep, which makes it more likely they’ll wake up during the night. This is completely normal – everyone, adults included, naturally wake up briefly at the edges of their sleep cycles (after dream sleep). What sets us apart is our ability to roll over and fall back asleep without even realising it. Babies, however, don’t yet have these independent sleep skills, so they may become upset if they wake up in a different environment than when they first fell asleep.  

Props – or things that help little ones sleep 

Just like adults, babies also rely on certain conditions to fall asleep – for them that might be a favourite blanket, rocking, a feed or even parental presence. When they wake up during the night and things are different, they may become confused or startled and need your help to get back to sleep and this can be overwhelming if they are waking as much as every sleep cycle. So, what can you do?  

4 tips to help prepare for this transition 

1. Keep the room dark: Newborns and young babies are very sensitive to light. Light can signal to their brain that it’s time to be alert. To encourage better sleep, make the nursery as dark as possible, especially during naps and bedtime. 
2. Use white noise: As your baby spends more time in lighter sleep, sounds may startle them more easily. Instead of trying to create total silence, use white noise to mask household sounds and help them stay asleep. 
3. Establish a simple bedtime routine: A consistent bedtime routine can help signal to your baby that it’s time to sleep. Keep it short—around 20 to 30 minutes. Avoid letting your baby fall asleep while feeding to prevent creating sleep associations that could make it harder for them to link their sleep cycles once they fall asleep. 
4. Get the timing right: Pay attention to your baby’s awake times. At four months old, babies can generally manage awake windows of up to two hours between naps. Aim for bedtime between 7- 8pm, as an overtired baby may have more difficulty settling down. 

Looking ahead 

Although the “four-month progression” can feel tough, rest assured that it’s a one-time transition. You may still face sleep disruptions later on, due to factors like illness, teething, or travel, but these are temporary and manageable. 

By teaching your baby the skills they need to fall asleep on their own, you’re helping them build a foundation for healthy sleep habits that will benefit them throughout their life. If your little one is reliant upon something to fall asleep and you are not sure how to help them adjust to independent sleep skills now might be a good time to consider a conversation with a sleep consultant.