How Do Babies Breathe In The Womb? My Midwife Set Me Straight

There I was, twenty weeks pregnant with my oldest, laying on a paper-covered table in a freezing room that smelled distinctly of industrial hand sanitizer and old magazines. The ultrasound tech was aggressively pushing the wand into my bladder when I saw it on the screen. My sweet, unborn child opened his mouth and seemingly swallowed a massive gulp of black, shadowy fluid. My heart dropped straight into my maternity leggings. I actually grabbed the poor tech's wrist and yelled, "He's drowning!"

I'm just gonna be real with you y'all, the amount of sheer panic I felt in that moment was unparalleled. My oldest, who's currently outside trying to convince our farm dog to eat a stray blue crayon, has always been my cautionary tale for everything medical. With him, I knew absolutely nothing. You read all these midnight forums where some exhausted parent is desperately typing "how do babi breathe" or searching for a "babie" lung development chart because they're doing that 3 AM panic-scroll with one eye open. Every single person who has ever carried a child has wondered how these little aliens are surviving in what's essentially a dark, watery balloon for nine months.

My grandma always swore that if you held your breath too long while watching a scary movie, the baby would suffocate in there. Bless her heart, she also thought drinking Dr Pepper while pregnant would make the baby come out with a tan. So, after I nearly tackled the ultrasound technician, my OB-GYN had to come in, sit me down, and explain exactly how babies get oxygen before they hit the outside world.

My doctor drew a spaghetti monster on a napkin

So from what I understand—and remember, I pack Etsy orders for a living, I don't wear a stethoscope—they don't actually use their lungs for oxygen while they're inside you. You're literally breathing for two. When you take a breath, the oxygen goes into your bloodstream, travels down to the placenta, and then zips through the umbilical cord straight into the baby's body.

Dr. Miller actually drew this out for me on a paper towel, and it looked like a plate of spaghetti. The placenta is apparently like a giant nightclub bouncer. It lets the good stuff like oxygen and nutrients pass through a membrane into the baby's blood, and it takes the carbon dioxide and kicks it right back out into your blood so you can exhale it. Your blood and the baby's blood never honestly mix, which still blows my mind.

As for their lungs? They're completely full of amniotic fluid. That gulp I saw on the screen was just him doing "practice breaths." Supposedly, by the third trimester, babies spend almost a third of their day just flexing their little diaphragm muscles, pulling fluid in and out of their lungs to get ripped for the big day when they finally have to take in real air.

The absolute psychological warfare of the umbilical cord

Let me tell you about the absolute worst part of pregnancy conversations, and it's always started by some well-meaning aunt at a church potluck who wants to tell you a horror story. The minute people find out you're pregnant, they want to talk about the umbilical cord wrapping around the baby's neck.

I spent my entire third trimester terrified of this. I was scared to turn over in bed too fast. I was scared to do yoga. My Aunt Linda pulled me aside at Thanksgiving to tell me about her neighbor's cousin's sister who had a baby with the cord wrapped around its neck three times. What Aunt Linda conveniently left out, and what my midwife later told me when I was having a meltdown in her office, is that this happens in like a third of all births and it's usually completely fine.

Because—and this is the part that makes me want to scream from the rural Texas rooftops—they don't breathe through their windpipes in the womb! A cord around the neck doesn't choke them because there's no air going through their throat anyway. The only time it's an issue is if the cord itself gets pinched so hard that the blood stops flowing, but the cord is covered in this thick, rubbery stuff called Wharton's jelly that protects the blood vessels from getting squished. My midwife said they literally just loop it over the baby's head during delivery like taking off a necklace.

And since their lungs are biologically designed to be completely filled with amniotic fluid until the very second they're born, drowning in the womb is literally impossible.

Getting ready for the real air

Eventually, they do have to come out and deal with actual oxygen, and that's when you get to smell that sweet babies breath that everyone talks about (before they start eating solid food and smelling like old cheese). But once they're out in the real world, their newly functioning respiratory systems and their brand-new skin are incredibly sensitive to everything in our environment.

I'm pretty budget-conscious, but with what sits against my babies' skin while they're adjusting to, you know, not being aquatic creatures anymore, I don't mess around. I'll absolutely rave about the Short Sleeve Organic Cotton Baby Bodysuit from Kianao. Listen, my second kid had an epic blowout phase that I thought would break me as a mother. I was washing clothes constantly. This ribbed organic bodysuit survived the trenches. It doesn't have those weird chemical smells when you take it out of the package, the envelope shoulders mean you can pull it down over their legs instead of over their head when disaster strikes, and it breathes so well. I'm cheap, but I'll happily hand over my money for something that doesn't shrink into a weird square after two washes.

If you're trying to set up a nursery that isn't full of synthetic junk, you might want to look into Kianao's organic collections.

On the flip side, people will try to sell you a million gadgets. We got the Panda Teether too. I'm just gonna be honest with you: it's fine. It's a piece of food-grade silicone shaped like a panda. It hasn't magically cured my youngest daughter's teething fussiness, but she likes the little textured bumps and it keeps her from trying to chew on the literal baseboards in my hallway, so I consider it a win for the price.

I also keep the Blue Fox in Forest Bamboo Baby Blanket draped over the rocking chair. When I was pregnant with my third, I'd just sit under it and try to get some rest laying on my left side while chugging enough ice water to stay hydrated, because supposedly that keeps the heavy uterus off some major vein and keeps the oxygen flowing to the placenta.

The big squeeze and the first cry

The craziest part of this whole breathing thing is the transition. Dr. Miller explained that during a vaginal delivery, the baby getting squished through the birth canal acts like a giant hug that literally squeezes a ton of the fluid out of their lungs. The rest of the fluid just gets absorbed into their bloodstream over the next few hours.

My second baby was an emergency C-section, so he didn't get that "big squeeze." When they pulled him out, he sounded super gurgly. Once again, I panicked. But the nurses were totally calm, grabbed a little suction bulb, and sucked the extra fluid right out of his nose and mouth so he could take his first real gasp of air. That first cry is the most aggressively beautiful sound you'll ever hear in your life, because it means the plumbing is working.

Pregnancy is just a giant exercise in realizing you've very little control over the biological magic happening inside your own body. You spend nine months as a walking scuba tank for a tiny person who's practicing breathing underwater, and then one day they're out here in the world, screaming because you gave them the wrong colored plastic cup.

If you want to keep that fresh, delicate newborn skin safe once they finally join us in the oxygen-breathing world, go check out Kianao's essentials. They genuinely hold up to farm life, three kids, and endless laundry cycles.

Shop the Kianao Organic Baby Collection here and save yourself some laundry-day tears.

Things you're probably still worrying about (FAQ)

Can my baby really not drown in the amniotic fluid?
I promise you, they can't. Their lungs are supposed to be full of fluid! They get 100% of their oxygen straight from your blood through the umbilical cord, kind of like an IV line for air. They don't need their lungs for breathing until they hit the open air.

What if the umbilical cord gets a knot in it?
This was my midnight panic search. From what my midwife explained, the cord is filled with a super tough, slippery gel (Wharton's jelly) that keeps the blood vessels from collapsing. True knots happen, but that jelly usually keeps the cord plump enough that the oxygen keeps flowing just fine.

Does it hurt the baby when I hold my breath?
Unless you're holding your breath until you pass out on the floor, no. Your body is incredibly smart and prioritizes the baby. Taking a deep breath before you sneeze or holding it while you drive past a smelly skunk on a backroad isn't going to cut off their oxygen supply.

Why do they monitor fetal breathing on late ultrasounds?
Towards the end, they want to see the baby doing "practice breaths" (moving their chest muscles). They aren't honestly breathing air, but seeing them flex those muscles tells the doctors that their brain and nervous system are developing correctly and gearing up for birth.

Are water births safe if they start breathing right away?
My doctor told me that babies have a reflex where they don't take their first actual breath until they feel the sudden change in temperature and the feeling of air on their face. In a water birth, they're just going from warm fluid to warm fluid, so they don't gasp and inhale pool water before they're brought up to the surface.