Ever feel like just as your baby finally settles into a good sleep routine, something changes? That “something” is often a new developmental milestone. Rolling, crawling, babbling, or sitting up, each one can temporarily disrupt your child’s sleep. But don’t worry, these phases are a normal (and healthy!) part of your baby’s growth.
In this blog, we’ll explore how developmental milestones impact baby sleep, and what you can do to help your little one get back to restful nights.
Let’s start with newborn sleep
Newborn sleep looks very different from older babies. They spend about 50% of their sleep in active REM sleep, where the brain processes information, forms memories, and builds neural pathways. That’s why newborns often appear to twitch, shuffle, or move in their sleep, they haven’t yet developed the muscular paralysis that stops us from acting out dreams. It can look restless, but it’s completely normal.
The other 50% of newborn sleep is deep sleep, often referred to as “sleeping like a baby.” During deep sleep, their bodies are hard at work:
- Renewing cells
- Releasing growth hormones
- Repairing the immune system
So both types of sleep – REM and deep – are crucial.
When sleep cycles start to form
Around 12 to 16 weeks, your baby begins to develop more adult-like sleep cycles. This means they’ll start to wake naturally at the end of each cycle, and how easily they return to sleep depends on how they’ve been falling asleep in the first place. If your baby relies on a “sleep prop” like rocking or feeding to fall asleep, they’ll likely need it again each time they wake in the night.
How developmental milestones disrupt sleep
There are four key types of milestones that can affect sleep:
- Gross motor skills (e.g., rolling, sitting, standing)
- Fine motor skills (e.g., picking up food, dressing themselves)
- Language acquisition
- Social development (e.g., engaging with others)
Here’s how each one can show up in your baby’s sleep patterns—and what you can do to help:
Rolling over
When babies learn to roll, they often want to practice it all the time – even in their sleep! They may roll onto their tummy and become stuck or frustrated. If this happens:
- Gently roll them back without talking or stimulating them
- Stay calm, even if you need to do it 50 times
- Offer lots of rolling practice during the day
Fatigued babies often forget how to roll back during the night, so extra daytime repetition is key.
Crawling
Crawling babies might wake in the night and get up on all fours to practice.
To help them through this stage:
- Give them plenty of practice during the day
- Model the movements if needed
- Stay consistent with your bedtime routine
Most babies move past this phase in just a few days with support.
Standing
This is a big one – babies who can pull to stand might not know how to get back down. If your little one is standing in the cot but can’t lie down:
- Calmly help them down
- Avoid chatting or engaging too much
- Give them practice during the day so they build the skill faster
Language leaps
Language development is one of the most overlooked causes of sleep disruptions in toddlers. You might put your 18-month-old down for a nap and hear them happily chatting for an hour. It’s tempting to think the nap isn’t needed anymore, but often, it’s a language acquisition not the end of nap time.
What to do:
- Let them have that quiet time, even if they don’t fall asleep
- If they’re under 2.5, it’s likely just a phase
- Watch for signs of afternoon fatigue – consider a short buggy nap around 3pm
- Move bedtime slightly earlier if needed
This phase usually passes within 2-3 weeks.
Stay consistent
Yes, developmental stages can wreak havoc on your baby’s sleep, but they’re also signs of your little one’s development. Your job? Support them without creating new habits that are hard to break later. Stay calm, stay consistent, and offer plenty of practice during the day. And remember: just because sleep is rocky now, doesn’t mean it will stay that way.
Need more help?
If developmental milestones have thrown off your little one’s sleep or their sleep has never been great, book a free 15-minute sleep chat to talk through what’s going on and how we can help.
