Basics Sleep

Why Do Babies Sleep With Their Arms Up? 5 Common Reasons

Have you ever lovingly gazed at your baby once they’ve fallen asleep, and noticed that they like to sleep with their arms above their head?

There’s no doubt this position is ridiculously cute, and somehow makes your little bundle of joy seem even more adorable than normal!

But curious parents often wonder why exactly do babies sleep in this position, and if it’s safe or something to be concerned about.

Babies tend to sleep with their arms raised up for several reasons, including because it’s comfortable, it helps them feel secure, and it can even enable a baby to breathe more easily.

Let’s find out more.

Why Do Babies Sleep With Their Arms Up?

Are you wondering why your newborn baby or infant often likes to sleep in a position with their arms above their head, or even with their hands behind their head?

Here are 5 of the most common reasons why:

1. Moro Reflex

The first reason comes down to something called the moro or “startle” reflex.

This is an involuntary reflex that is a response to stimulation and is something that naturally goes away once your baby reaches 3 to 4 months.

When your little one is asleep in their crib, they can often feel as if they are about to freefall, and in response, they throw their arms and legs out in order to try and catch themselves.

And as you can imagine, when this reflex kicks in it can startle your baby and cause them to wake up.

So one of the reasons why a baby will sleep in this position is because it lets them know they are resting on a firm surface (mattress) and reassures them there is no need to feel unsafe or insecure.

Sleeping with arms in the air is clearly a good thing for parents and babies alike, because it will not only decrease the chances of your baby suddenly waking up, but will also make it easier for them to sleep somewhere other than in your arms or on your chest.

Related: The Ultimate Guide To Baby & Toddler Sleep

2. It’s Comfortable

The second reason why your baby likes to sleep with their arms raised up is a very understandable one, and that’s because it’s comfortable!

We all have our favorite or preferred sleeping position – many toddlers for example like the butt in the air position, and your newborn is no different when it comes down to having a favorite position.

The arms-up position is also likely to be a comfortable one because there aren’t many other options to choose from when a baby is safely sleeping on their back (the recommended position to reduce the risk of SIDS).

If you’re not using a swaddle, then when sleeping on their back a baby can effectively put their arms in three positions; by their side, on their body or above their head.

So if your little one opts for the latter of those three options, it might well be because that’s what feels most comfortable to them.

3. To Stretch

There is no denying that the womb is a very comfortable, safe, and secure place for a baby.

But if there is one thing that it’s lacking then it’s space, so there is very little room for your baby to stretch and move when inside mommy’s tummy.

The ability to now stretch out to their heart’s desire, and freely move their arms as high above their head as they want, may therefore be another reason why your baby likes to sleep or nap in this position.

Baby Lying Down Stretching

4. To Cool Down

In the warmer summer months, it’s recommended you put your baby to sleep wearing lightweight fabrics in a room that’s 68-72 degrees Fahrenheit.

This should help ensure your baby doesn’t overheat, which is important because newborn babies may not be able to regulate their own body temperature until they are around 3 months old.

But there may still be times when your little one will feel too warm, and putting their arms up will allow them to cool themselves down.

As a side note, when sleeping in winter your baby may do the opposite and keep their arms by their side in a bid to stay warm, which might be an indication you need to dress them in another layer or use a sleep sack or pajamas with a higher TOG rating.

5. Easier To Breath

Did you know that pulling your arms up and away from your torso makes it easier to breathe?

The reason is that this position can help open your lungs and expand the muscles that line your ribs, therefore making it easier to take a deep breath.

So by placing their arms above their head, your baby is able to open up their diaphragm and chest, making it easier to take deep breaths, and this could also be a reason why your little one favours this sleeping position.


  • It’s very common for a baby to sleep with their arms above their head.
  • This position is natural and safe, so there’s nothing to worry about, and no need to move your baby’s arms or put them back down by their side.
  • The most likely reason for sleeping in this position is because it helps keep the Moro or “startle” reflex in check.
  • Other possible explanations are that it’s comfortable, easier to breath,e and a way to cool down.

Tori is mama to 3 year old Isabella and co-founder of Rockinbaby. She has a BSc in Psychology, is a certified yoga teacher and is a working mom. In her free time Tori loves cooking delicious foods and baked treats, entertaining and working out. Learn more about Tori here.

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