How Do Babies Breathe in the Womb? Nurse’s Viral Explanation

How do babies breathe in the womb? I honestly have no idea! I’ve had three kids and I’ve never even considered how they breathe in there, especially when they are surrounded by water.

Luckily Nurse Jen knows the answer and has explained it to us. Here’s how it works:

How do babies breathe in the womb? We’ll show you! 

Nurse Jen Hamilton shared her easy-to-understand explanation of how babies breathe in the womb on her TikTok account and we, like thousands of others who have watched it, are blown away.

Before she explains how babies breathe in the womb she answers another question you probably didn’t realise you needed to know the answer to. How do babies swim around in a pool of water for nine months and not have their skin wrinkle and peel off?

The answer: Vernix, the thick waxy substance that covers bub’s skin. This vernix is responsible for protecting their skin from falling off while they chill out in amniotic fluid for several months. Makes sense, right?

Doctor Puts Her Own Birth On Hold To Deliver Baby
Vernix. The ultimate in baby skincare! Source: Bigstock

But what about the whole breathing thing? When babies are in utero they don’t use their lungs to breathe. In fact, their lungs are filled with fluid which helps to support their development and growth.

“While your baby is inside of you, there are two vessels. These vessels bypass the lungs cause it’s getting all of its oxygen from you,” Nurse Jen explains.

Instead of breathing through their lungs, oxygen is supplied to bub through the umbilical cord.

How do babies know it’s time to start breathing on their own?

Okay, so how do babies know that they need to breathe when they come out of the womb then? This part is really cool. As Nurse Jen explains, it all comes down to a special nerve in their face that alerts them that now it’s time to breathe.

“When the baby’s face hits air, there’s a nerve in the face called the trigeminal nerve. That tells the baby, ‘I would like to breathe air now’ and it begins to switch its circulation from the umbilical cord to air,” Nurse Jen shares.

The switch doesn’t happen immediately and it can take a few minutes for the baby to get the hint that it’s time to breathe on their own, which is why delayed cord clamping is so important.

Now, one more question – what happens to all the water in the baby’s lungs?  Nurse Jen has a perfectly logical explanation for that too:

“When the baby gets pushed through the birth canal, their chest gets squeezed which can push out some of the fluid that’s in their lungs.”

She also goes on to explain that often babies that are born via c-section may have a little bit of trouble making this breathing transition.

Babies and hiccups

Okay, one final fun fact. It’s actually hiccups that are responsible for teaching your baby how to breathe in the womb.

“Under your baby’s lungs is a muscle called the diaphragm. Hiccups are a spasm of the diaphragm. Whenever we get hiccups it sucks air into our lungs really quickly, which is what makes that sound when air passes through our vocal cords.”

She goes on to explain that when babies get hiccups the spasm is expanding their lungs by filling with amniotic fluid, which is how babies practice breathing. My third little one was a Hiccup Queen in utero – guess she needed all the practice she could get!

It’s a lot to take in but it’s pretty cool, right? New fact of the day, unlocked.

Check out Jen’s now-viral video below for her simple explanation of it all.


#stitch with @Cori

♬ original sound – Jen Hamilton

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If you’re looking for more fun facts about babies check out:

Avatar of Jenna Galley

Born and raised in Canada, Jenna now lives in Far North Queensland with her tribe. When the mum-of-three is not writing, you can find her floating in the pool, watching princess movies, frolicking on the beach, bouncing her baby to sleep or nagging her older kids to put on their pants.

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