Most of us buy baby clothes by look and feel. The label goes unread, and even when you do read it, it's a list of words that don't explain themselves. Polyester. Viscose. Elastane. Cotton blend.
So here's the plain-English version: what those words actually mean, which fabrics shed plastic into your washing machine, what the research does and doesn't tell us, and how to read a label in about four seconds.
Baby-clothing fabrics come in three families
Nearly everything in a baby's drawer belongs to one of three groups.
- Natural fibers grow. Cotton, wool, linen, silk. They come from a plant or an animal, they're not made from oil, and when they eventually break down, they break down into things that were already part of the world.
- Semi-synthetic fibers start natural and get processed. Rayon and viscose are the common ones. They begin as wood pulp, which is then chemically dissolved and re-spun into thread. They're often sold under brand names that sound proprietary, but the underlying fiber is wood cellulose. These are not plastic, and they aren't the concern of this article. They're plant-derived and they biodegrade.
- Synthetic fibers are plastic. Full stop. Polyester, nylon, acrylic, elastane (also called spandex), polypropylene, acetate. All of them are made from fossil fuels. Polyester is the same family of plastic as a drink bottle. Elastane is what gives a garment its stretch, and it turns up in small percentages in an enormous number of baby clothes: 95% cotton, 5% elastane is a label you have seen a hundred times.
That last family is now most of what the world wears. Roughly 64% of all clothing fiber produced is synthetic.
The part nobody mentions: synthetic clothes shed
Plastic clothing doesn't stay whole. Every time it moves through water or rubs against itself, it releases microscopic plastic threads called microfibers.
The numbers are not small. A single wash load of synthetic fabric can release more than 700,000 plastic microfibers. Washing synthetic textiles is estimated to account for roughly a third of the primary microplastics entering the ocean, which puts laundry among the largest single sources on earth.
If that sounds abstract, here is what it looks like on the ground. When the National Park Service, Clemson University, and the NOAA Marine Debris Program sampled 37 national park beaches, they found microplastics at every single one. And of everything they counted, microfibers made up 97%.
Not bottle caps. Not fragments of old buckets. Threads. It was a snapshot study, one sampling point in time, so read it as a photograph rather than a trend line. But it's a striking photograph: go to a protected American beach, sift the sand, and nearly everything synthetic you find came off of fabric.
And it isn't only the washing machine. Research from the University of Plymouth found that synthetic clothes shed microfibers while you're simply wearing them, into the air of the room you're standing in.
These fibers don't biodegrade. They pass through wastewater treatment, into rivers and oceans, get eaten by marine life, and move back up the food chain.
How you wash matters, too. Research on domestic laundering found that powder detergent sheds more than liquid. The abrasive particles scour the fabric as it tumbles.
What you can do today: use liquid detergent, wash your laundry at lower temperatures, and run fuller loads. Nobody's replacing their whole wardrobe this week, and you don't have to in order to shed less.
Where they end up
This is the part that has changed fastest in the last few years.
In 2022, researchers testing the blood of healthy adults found microplastics in 77% of the samples. Plastic particles have since been identified in human lungs and in the placenta. In 2025, they were found in brain tissue.
So the presence question is settled. Plastic particles are in human bodies, including very small ones.
What plastic does once it's in a human body is still being studied; the World Health Organization's position is that we urgently need to know more.
"But doesn't cotton shed too?"
Yes. And we'd rather tell you than let you find out somewhere else.
Every fabric sheds. Wash a cotton onesie and cotton microfibers come off it. The difference isn't whether fibers come off. It's what those fibers are, and what happens to them next.
This is how everything in nature has always worked. A branch falls, breaks apart, and decomposes back into the ground it came from. Shedding isn't the problem. Shedding is the normal condition of every material thing. A cotton fiber coming off in the wash is doing what a fallen leaf does. It's cellulose. It goes back.
A polyester fiber doesn't go back. It isn't returning to anything, because there's nothing for it to return to. It was made from oil, and it stays plastic. It accumulates: in the water, in the fish, and then in what we eat. That's not decomposition. That's just pollution with extra steps.
How to read a label in four seconds
Turn the garment inside out and find the composition tag. Then:
- "100% cotton": a plant. Sheds cellulose, not plastic. - "100% organic cotton": a plant, grown without synthetic pesticides. Better for the soil and the people farming it.
- Elastane, spandex, polyester, nylon, or acrylic: plastic, and it will shed. A 5% elastane blend is still a plastic-shedding garment.
- Rayon or viscose: wood-derived, not plastic. Fine on the microplastic question; check the rest of the label for a blend.
The single most useful habit: look for the word "blend," then find out what it's blended with. "Cotton blend" is doing a lot of quiet work in that sentence.
Why we made the choice we made
Our onesies are 100% GOTS-certified organic cotton. No elastane, no polyester, no blends.
It's a small choice. It has no downside. And in a category where nearly everything now contains some percentage of plastic for the sake of stretch, it's a choice worth making on purpose.
This subject isn't academic for me. Because of my own health issues, what we're exposed to, and how much of it accumulates without our noticing, became something I pay very close attention to. That's the lens I brought to this company, and to my daughter's drawer.
She's going to grow up with more exposure around her than we can control: chemicals, plastics, heavy metals, things that probably don't have names yet. We can't prevent that, and we don't trust anyone who claims they can. What we can do is not add to it in the places where the choice is genuinely ours. What she wears against her skin every day is one of those places.
It's the same standard we hold at home. Cotton, linen, silk, wool. The things that grow.
Sources
- Microplastics in human blood: Environment International (2022) - Microplastics in placenta and lung tissue: Environment International (2021); Journal of Hazardous Materials (2021) - Microplastics in brain tissue: Nature Medicine (2025) - Textiles as a share of primary ocean microplastics: IUCN (2017) - Microfibers as 97% of debris counted across 37 national park beaches: National Park Service / Clemson University / NOAA Marine Debris Program - 700,000+ fibers per wash load: Napper & Thompson, Marine Pollution Bulletin (2016) - Polyester garments shedding >1,900 fibers per wash: Browne et al., Environmental Science & Technology (2011) - Cotton, rayon and polyester shedding compared, and their aquatic biodegradation: Zambrano et al., Marine Pollution Bulletin (2019) - Detergent type and microfiber release during domestic washing: De Falco et al. (2018) - Shedding during wear: University of Plymouth (2020) - Microfiber release in the EU: European Environment Agency (2022) - 64% synthetic share of global fiber production: Textile Exchange - Health mechanisms under investigation: International Journal of Molecular Sciences review (2025) - "We urgently need to know more": World Health Organization (2019)