3 Reasons Why Babies Sleep With Their Butt in The Air

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Babies are adorable when they’re sleeping, but did you know there is a reason why they adopt that funny habit of sleeping with their bums in the air? We often don’t consider why we position ourselves a certain way while resting. What’s comfortable for one person may be painful for another.

There is scientific evidence explaining why babies sleep with their butts in the air, and we explain why it’s comfortable for our precious little ones.

Why Do Babies Sleep On Their Knees?

Our children enjoy sleeping with their legs curled under them because it’s how they were positioned pre-birth. It simulates their cozy days in the womb.

Sleeping Curled Up Reminds Them of the Womb

When your little one is tuckered out with their knees pulled up under them, they’re likely dreaming of one of their favorite places—the womb. If they’re still young, they may have spent more time curled up inside than in the real world so far.

Muscle memory is a real thing, and this frog-like pose can be attributed to the fact they were positioned with their knees tucked up inside a belly for nine months.

Naturally, we all move in ways that feel comfortable to us. Some people like to stand up straight with their hands on their hips; this doesn’t mean they’re trying to look authoritative, their limbs may feel most natural this way, and kids want the same.

Many adults can’t imagine sitting on a floor cross-legged. As we age, we’re often too tall or no longer flexible. Infant bodies are much more malleable than ours, and we’ll likely see all kinds of funny positions as they continue to grow.

illustration of a stomach sleeper baby

Baby Is Learning to Crawl

A newborn’s muscles can be tight from being cocooned inside of a belly for nine months, lacking the ability to stretch. As your child grows, their muscles develop. With time, these ligaments will lengthen and loosen up, allowing them to eventually sprawl out in positions that seem more relatable to adults.

Until then, they’ll assume the bum position they got used to while sleeping in the belly.

Additionally, the pose your munchkin takes when they’re fast asleep with their bum in the air is notably similar to the one they make when they’re learning to crawl. When they’re getting ready to crawl, you might see your little one on the floor with their limbs underneath them, rocking side to side until they figure out how to propel themselves forward. As they get older, their body will change to accommodate growth spurts in development, allowing them to crawl and walk.

Illustration of a Baby Crawling with Toys all around Them

It’s Comfortable

If you’ve ever taken a yoga class, chances are you’ve laid in “child’s pose.” This position is remarkably similar to how a youngster sleeps with their bum in the air. There’s a reason this pose is a pillar in the yoga world; it provides benefits for both your body and brain. This resting position calms and centers the mind, making this therapeutic position conducive to stress relief.

By laying in this position, it relieves the tension a little one’s body has absorbed throughout the day. Paired with deep breathing, it further encourages oxygen and blood circulation to restore energy so your body can perform it’s best.

Frequently Asked Questions

Should I Keep Flipping My Baby Onto Their Back?

No, you don’t need to flip your baby onto their back once they flip over on their own. If they turn onto their sides or tummies while sleeping, that’s an indication they’re growing stronger.

Once they’re mobile, they’ll be able to push themselves up or around to their back on their own. Having that physical practice of learning how to move independently is an essential component of your infant’s growth.

However, placing them on their backs when you put them to bed is wise, as it’s the safest position to sleep in, reducing the risk of SIDS.

Find Out More: Parent's Guide to a Child's Sleep

Is It Dangerous For Babies To Sleep With Their Bum In The Air?

Once your little one has started to turn over on their own, it’s no longer necessary for you to manage how they sleep, as they’ll be able to move into positions they prefer autonomously. Kids may end up in all kinds of funny positions while they sleep, which is entirely reasonable. Check out our best mattresses for kids to give them that freedom of movement while they sleep.

Once they can move, it’s no longer necessary to swaddle them, and they can transition to sleep sacks. At this point, when our young ones start becoming independently mobile, wrapping them up in a swaddle can, in fact, harm them. This is because once they wiggle out of a swaddle, it can cause them to get stuck in their blanket or suffocate.


Naturally, we want to be present for every moment to watch our children grow and change. We want to capture their first bath, first steps, first words—we don’t want to miss a thing. There are countless lessons to learn when we raise children. It’s an important job and our little monsters depend on us.

It’s essential to find joy in moments of confusion and laugh at ourselves for the silly mistakes we make and at the astonishing characters our little ones are blossoming into. Whether your kiddo sleeps with their bum in the air or sprawled out like a ragdoll, they’re each their own unique individual, and that’s part of the fun.

Katie Simpson
Sleep Advisor