The Great Onesie Lie and Why Newborn Long Sleeve T Shirts Win

Sarah
2026-03-26T00:40:32+01:00

I'm standing in the nursery, it's like 3:14 AM, I'm wearing a nursing bra that smells vaguely of sour milk and Dave's oversized college sweatpants, and I'm practically in tears over three tiny metal crotch snaps. Before you've a baby, the entire internet basically brainwashes you into believing that your child will live, sleep, and breathe in snap-bottom bodysuits. They sell them in packs of ten! They have cute little bears printed on the butt! It's a total lie. The biggest lie of modern motherhood, honestly.

Because nobody warns you about the umbilical cord stump. They just send you home from the hospital with this tiny, fragile human who has a crusty, blackish-purple piece of decaying flesh attached to their abdomen with a weird plastic clip, and you're supposed to just dress them normally? If you put a traditional bodysuit on a fresh baby, you're literally pulling a taut piece of fabric directly across a healing wound every single time you snap it closed. It makes zero sense. I'm here to tell you that standalone newborn long sleeve t shirts are the unsung heroes of the fourth trimester, and we need to talk about why.

That crusty little belly button changed my whole personality

With my first kid, Leo, I was absolutely terrified of his belly button. I wouldn't even look at it when I changed his diaper. I was so paranoid that I was going to accidentally rip the stump off while wrestling him into his clothes that I basically stopped using the onesies we got from our baby shower. I just couldn't handle the friction. You have to snap them so tightly over the diaper, and it just traps all that moisture and pressure right against the one part of their body that desperately needs air to heal.

What you actually want for those first three weeks of newborn purgatory is a loose, flowy top. I had this one specific shirt, the Organic Cotton Baby Shirt Long Sleeve Ribbed from Kianao, and I'm not exaggerating when I say I washed it in my bathroom sink every single night because it was the only garment I felt safe putting him in. It's an actual shirt. No snaps at the bottom. The ribbed fabric is super stretchy so you aren't fighting to bend their tiny, rigid little arms into stiff sleeves, and it just gently drapes over the belly button.

No pressure. No rubbing. The air can actually get to the stump. Leo's dried up and fell off in like seven days, and I swear on my life it was because it wasn't suffocating under a snapped-down bodysuit. Anyway, the point is, regular shirts are incredibly underrated for fresh newborns. Also, don't even get me started on those tiny baby scratch mittens, they fall off in three seconds and are a total joke, just focus on getting the shirts right.

Dave's irrational fear of the tummy gap

thing is everyone always complains about with infant t-shirts, and the reason my mother-in-law told me I was crazy for using them: they ride up. Yes, they do. Because you're constantly picking the baby up, putting the baby down, passing the baby to visitors who insist on holding them like a football, the hem of the shirt inevitably ends up somewhere around their armpits.

My husband Dave used to follow me around our apartment constantly pulling Leo's shirt down over his diaper. "Sarah, his belly is out, he's going to freeze," he'd whisper, while standing in our living room that was currently heated to a balmy 74 degrees. Let me tell you, babies don't spontaneously freeze because two inches of their stomach is exposed to central heating. The ride-up is actually a feature, not a bug, at least during the cord-healing phase. It gives you instant access for diaper checks without having to un-snap anything in the dark.

Although, I'll admit that once the belly button is completely healed and you're moving into month two or three, that's when you can finally transition back to bodysuits without feeling like a monster. The Long Sleeve Organic Cotton Baby Bodysuit is totally fine for later on, especially when they start rolling around and seriously doing tummy time under their Panda Play Gym (which is adorable by the way, it has this little crocheted star that Maya used to just stare blankly at for forty minutes while I reheated my coffee in the microwave). But for those very early days? The snap-crotch is the devil. Just let the belly hang out.

What Dr. Aris said about the sun and toxic baby skin

Let's talk about summer babies for a second, because Maya was born in July during a massive heatwave. We live near a lake, and I had this whole ridiculous fantasy of bringing her to the beach in a little bucket hat and just slathering her in baby SPF 50. Yeah, no. I took her to her two-week checkup and casually mentioned my grand beach plan, and my pediatrician, Dr. Aris—who's usually the most relaxed guy on the planet—literally stopped typing on his laptop and just stared at me.

He told me that putting sunscreen on a baby under six months old is a massive medical no-no. He said something about their skin being paper-thin and basically acting like a giant sponge that sucks chemical filters straight into their little bloodstreams, which I'm probably misquoting or exaggerating, but the point is he made it sound like I was going to accidentally poison my child with banana boat.

So how are you supposed to protect them from the sun? You have to use physical barriers. A newborn long sleeve is basically a wearable parasol. You have to keep their arms and torso completely covered if you're outside. But if you put a tiny baby in a thick, heavy cotton top in the middle of July, they're going to overheat in about five minutes. Overheating is terrifying, by the way, it's a huge SIDS risk and it kept me up at night constantly touching the back of Maya's neck to see if she was sweaty. This is where you honestly have to start paying attention to what their clothes are made of.

My granola sister-in-law was genuinely right about the fabric thing

I used to roll my eyes so hard at people who insisted on buying organic everything. I figured a cheap multipack of shirts from a big box store was just as good as anything else, because they're just going to poop on it anyway, right? But regular conventional cotton is apparently heavily treated with pesticides, and polyester blends are basically just the equivalent of wrapping your child in a plastic grocery bag.

Explore Kianao's organic cotton baby collection to see the difference for yourself.

If you're using a long sleeve shirt as a literal sun shield in the middle of a ninety-degree summer day, it has to be breathable. It has to be organic cotton or bamboo. When I finally caved and bought the organic ones from Kianao, the difference was wild. The fabric didn't trap the heat against Maya's back. When I took her out of her car seat after a drive to my mom's house, she wasn't a damp, sticky, red-faced mess. The heat could honestly escape through the material.

And for winter babies? Same rules apply, just with thicker layers. We used the Organic Baby Romper Long Sleeve Henley when the weather finally turned freezing, and because it's organic cotton, it kept her warm without making her sweat under her winter coat.

The Starbucks blowout incident of 2017

You know how all those well-meaning parenting books tell you to somehow stretch the neck hole of a shirt while simultaneously pinning your baby's flailing little octopus arms to their sides and swiftly sliding the garment over their head before they realize what's happening and start screaming bloody murder? Yeah, ignore all of that and just buy shirts with envelope necklines instead.

An envelope neckline is the one with those little folded, overlapping flaps at the shoulders. It means you can stretch the neck hole incredibly wide and pull the shirt down over their body instead of up over their giant, wobbly newborn head. Putting a tight crewneck over a screaming infant's head is a form of psychological torture I wouldn't wish on my worst enemy.

I learned this the hard way during a specific blowout with Leo. He was maybe four weeks old. We were at a Starbucks downtown. He was wearing a very cute, very stiff, very expensive little boutique sweater that my aunt gifted us. No shoulder flaps. Just a tiny, rigid neck hole. I was changing him on this tiny plastic fold-out table in the bathroom, and I realized the poop had traveled all the way up his back to his shoulder blades. Because of the neck hole, I had to pull a mustard-yellow, poop-covered sweater up and over his ears and hair. I was sweating through my shirt. I was crying. The barista who knocked on the door to see if I was okay looked terrified when I finally emerged. From that day on, I only bought envelope necklines. You just shimmy it down over their hips, trap the mess inside, and throw the whole thing in a wet bag.

The baby clothing industry wants you to buy fifty different complicated outfits with matching hats and tiny stiff jeans. You don't need any of it. Just get some soft, stretchy shirts that don't trap their belly buttons, and forgive yourself for leaving the house in sweatpants.

Ready to ditch the complicated snaps? Shop our collection of umbilical-friendly organic newborn shirts here.

Messy, Honest FAQs About Newborn Shirts

Do newborns really need long sleeves in the summer?

Oh god, yes. Unless you're keeping them in a dark, air-conditioned cave 24/7. Like Dr. Aris told me, you can't put sunscreen on a baby under six months old because their skin is basically a sponge for chemicals. So if you're taking them for a walk in the stroller, they need a physical barrier against the sun. Just make sure it's a super lightweight, organic cotton shirt so they don't roast.

How many of these shirts do I seriously need to buy?

Honestly? Like, six to eight. I know the minimalists on Instagram will tell you that you only need three capsule wardrobe pieces, but those people apparently don't have babies who spit up curdled milk three times an hour. You're going to be doing laundry constantly, but you still want enough shirts to get you through a 3 AM outfit change without crying.

What's the big deal with the envelope shoulders?

Poop. It's all about the poop. When your baby inevitably has a massive blowout that goes all the way up their back, you don't want to pull that soiled shirt over their head and get it in their hair. The envelope flaps let you pull the neckline wide open and slide the whole messy shirt down over their feet. It will save your sanity.

Are snap-crotch bodysuits completely terrible?

No, they aren't completely terrible forever, I just deeply hate them for the first month. Once the umbilical cord stump falls off and heals completely, bodysuits are totally fine. I honestly love them for when babies start crawling so their knees don't pull their clothes off, but for those first few weeks? Stick to the loose shirts.

Will my baby freeze if the shirt rides up?

Dave certainly thought so, but no, they won't. If you're inside your house and the temperature is comfortable for you in a t-shirt, your baby is not going to get hypothermia because an inch of their tummy is showing between their shirt and their diaper. Let it ride up. The fresh air is good for their belly button anyway.