How Developmental Milestones Affect Sleep

Sleep was great!… your baby slept through the night, went to sleep independently… THEN, all of a sudden something changed. Are they going through any developmental milestones?

How old is your child? 

What are they doing that’s new? 

Are they about to reach one of their development milestones?

…THIS could be the reason.

Let’s say your child is about to walk, that right there can be what is affecting sleep. Not even a single step but it’s now reeking havoc in their sleep. Crazy right?

Think of it like this, rolling, walking, talking are all huge developmental milestones in your child’s development. It takes a lot of energy for their body and mind to master these tasks. Therefore, that is all their mind can think about. It’s on overdrive and cannot settle down. If their mind can’t settle, they can’t sleep.

What happens next is what makes all the difference. You start to go in and rock him to get him back to sleep or maybe (depending on the age) a feeding now gets introduced again. Reverting to old things because no one knows why this is happening and what to do about it. 

I caution you on doing that.

There are many things that causes a child to have a rough night. It could be illness, a tooth coming in, an upset tummy, constipation or gas, cold or hot. Many factors that you are trying to figure out. If it still is a mystery as to why your child is now struggling with sleep then keep reading. 

In a 2015 study published in Monographs of the Society for Research in Child Development, researchers looked at the sleep patterns of babies. Before they started crawling, while they were learning to crawl, and a few months after learning to crawl. 

The results stated that, “Along with the overall improvement in sleep consolidation, periods of increased long wake episodes were also manifested; the rise in sleep disruption was temporally linked to crawling onset. The results of the study highlight the dynamic interrelations between domains of development, indicate that emerging motor skills may involve periods of disrupted sleep, and point to the moderating effect of age.”

Let’s take a look at these developmental milestones and the general ages they can occur.

Disclaimer: I’m going to give you an age range, you may have an early walker or talker or a child who takes their time.


Rolling both ways – 4 to 6 months

At this age, babies are very active during their rapid eye movement (REM) sleep stage. Because of this, your baby could is performing a new skill, like rolling and then feel “stuck.” They wake uncomfortable and uncertain of how they got there. Don’t be surprised once your baby gets the hang of rolling, they may prefer to sleep on their tummies. Just not until then. 

The American Academy of Pediatrics does suggest laying your baby down to sleep on their backs. Even if you know your baby prefers their belly. Lie them down on their back, even when your baby knows how to roll.  They can move themselves. This is part of the self-soothing we are teaching them. At this time, STOP swaddling your baby. It is no longer safe when they are at this age and show signs of rolling. 

So what are you supposed to do?


As you know, practice makes perfect. You need to practice the skill of rolling with your kiddo. Lay them on a blanket and gently pull them over so they begin to learn the sensation of switching into that position. This will help them through not feeling surprised when they do this skill at night. 

When your baby rolls in the middle of the night, and they cannot yet roll both ways on their own, then you need to go in and roll them back over. Do this gently and quietly so they can easily go back to sleep.

When your baby shows you they can roll both ways independently, then you no longer need to roll them back over in the middle of the night. I know you’ll be on edge until you all get used to this but it will happen. This is also a benefit of a video monitor!


Sitting up and crawling – 6 to 12 months

First and foremost, when your baby is sitting up, it’s time to lower that crib mattress. The top bar should be above their head when they are sitting up. 

When they can sit up and craw you will start to see your baby moving a lot more after putting them down to sleep. They may even bump into the side of the crib. There’s not much you can do about this, buying products to soften the blow are just unsafe and are not recommended in their crib. 

At this age, your baby is at a perfect age to develop independent sleep skills. If they have them, you may not see this regression very much, but if they don’t, prepare for it. Remember don’t change their routine but also begin to teach them independent sleep skills and lay them down awake. 


Supported standing 9 to 10 months

Though your baby was on the move before? Now they will be all over that crib and vertical while doing it. Let your baby explore explore this. Soon standing for them will be normal but until then they need to figure out how their legs work.

Put the crib mattress is on its lowest level. The last thing you want to see is a leg being lifted over the top of the crib rail. 

When your baby can stay, they need to practice bending their legs and laying down and going to sleep themselves. If you have been rocking your baby to sleep and laying them down in the crib, then when they wake in the middle of the night they won’t know how to get themselves back to sleep. They literally won’t understand that they need to bend their legs to lay down to go back to sleep because it has been done for them for so long. 


Walking – 11 to 15 months

This tends to be a big one and why not because walking is such a big milestone. Grab your running shoes, your baby is officially on the move!

Lastly, increase in verbal – 18 to 24 months

These are the popular developmental milestones. It doesn’t mean your child will be sensitive to all of these developmental milestones, maybe just one, but it’s possible for all to affect them as well.

Here’s what you do about these developmental milestones

Like I said, the BEST thing to do, hold steady. You will need to soothe them more than usual, help get them out of an uncomfortable position if they wiggled themselves into one, tell them it’s bedtime and allow them to self-soothe to go back to sleep.

It may seem tough now, but I promise the quick fixes won’t last long and will cause more angst for you and baby in the long run. Hang in there, the whole time your baby is working through this they are also learning how to consolidate nighttime sleep and soon this will pass. 

If the room setting also isn’t ideal that’s where you can start. Check out my blog on blackout curtains. 

Set up a call and we can chat about what your child is developmentally working on.