Microplastics in pregnancy: what is known so far for mothers and babies

Microplastics — plastic fragments smaller than five millimetres — and nanoplastics, far smaller still, are now found almost everywhere, including inside us. For PFAS, decades of research allow health agencies to say with some confidence what exposure in pregnancy does. For microplastics that research has only just begun. It is certain that they reach the mother, the placenta and the baby. What they do there is, for the most part, not yet known.

So this page does two things. It sets out what has been found, and it says plainly how strong each finding is — a large study or a small one, a conference presentation, or an experiment in animals. Those are very different kinds of evidence, and a worried parent deserves to know which is which.

What has been found in mothers

• In the placenta — every one tested. In a 2024 study at the University of New Mexico, researchers found microplastics in all 62 placentas they examined, most of it polyethylene, the plastic of bags and bottles. In Hawaii, placentas containing them rose from 60 per cent of samples from 2006 to every sample from 2021. The New Mexico team said openly that it is not yet clear what health effects this has, if any.
• Premature birth: an early signal. In a study of 175 placentas presented at the Society for Maternal-Fetal Medicine’s 2025 meeting, those from premature births held significantly more micro- and nanoplastics than those from full-term births. It was a conference presentation rather than a full paper, and it cannot show that the plastics caused the early births.
• High blood pressure in pregnancy: an early signal. A small study from China compared 15 women with pregnancy-induced hypertension, including pre-eclampsia, with 30 women without it. Their umbilical cords held about one and a half times as much microplastic. It is a lead worth following, not yet a finding.
• The chemicals the plastic carries. Plastics contain additives such as phthalates and bisphenol A (BPA), which can interfere with hormones, and pregnancy is one of the most sensitive times for that. Part of the concern is these chemicals, not only the particles.

What has been found in babies and children

Microplastics have been detected in the placenta, in amniotic fluid and in meconium — a newborn’s first stool — so exposure begins before birth. After birth it continues through feeding, and through everything a baby puts in its mouth.

• Growth before birth: very small studies so far. A 2024 review of the twelve human studies then available, with 234 participants between them, found that higher exposure went with lower birth weight and length in pregnancies where the baby was not growing well. Its authors stress that every one of those studies was extremely small.
• Feeding bottles. Heat is what makes plastic shed. In a 2020 study in Nature Food, polypropylene feeding bottles released up to 16 million particles per litre when formula was made with water at 70°C, as safe-preparation guidance requires, and more at higher temperatures. A 2025 review estimates that bottle teats alone may add over 660,000 particles a year.
• More than adults. Microplastic concentrations in babies’ stool have been reported at about ten times those in adults’.
• Brain and gut: animal studies only. In pregnant mice, plastic particles pass from the mother to the developing brain, and they inflame the gut and disturb its bacteria. Whether the same happens in human babies, and what it would mean, is not known; the large human studies needed to answer that do not exist yet.

What you can do

This is one area where small, everyday changes make a real difference, above all for a baby fed from a bottle. The researchers behind the feeding-bottle study were careful not to alarm parents; they pointed to simple changes instead.

• Keep hot liquids out of plastic. Glass or stainless-steel bottles avoid the problem. With plastic bottles: after sterilising, let the bottle cool and rinse it three times with cooled boiled water; make up the formula in a glass or other non-plastic container, following the usual safe-preparation instructions, and pour it into the bottle once it has cooled.
• Do not reheat formula or food in plastic, in the microwave or anywhere else, and do not shake hot formula in a plastic bottle.
• Bottled water is not the way out. A 2024 study counted around 240,000 plastic particles in a litre of bottled water — more on that in our article. Filtered tap water is usually the better choice.
• Keep breastfeeding.

Why this matters to us

There is still no enforceable limit for microplastics in drinking water anywhere. The Foundation funds water systems at the tap for children’s homes and shelters in Greece, and in New York and New Jersey we are building partnerships with organisations that house pregnant women, young mothers and their babies. For homes like these, a system paid for once and serviced regularly is a better answer than bottled water bought every week: cheaper, and without the plastic.

If you would like to help, the ways to give are on our donate page.

Sources

1. University of New Mexico Health Sciences, microplastics found in every placenta tested, Toxicological Sciences (2024).
2. Harvard T.H. Chan School of Public Health, Microplastics and women’s health: what we’re learning from new research (2026), including the Hawaii placenta series.
3. Society for Maternal-Fetal Medicine, high concentrations of plastics in the placentae of infants born prematurely, The Pregnancy Meeting (January 2025).
4. Microplastic exposure in daily life and the risk of pregnancy-induced hypertension, Journal of Hazardous Materials (2025).
5. Impact of microplastics on pregnancy and fetal development: a systematic review, Cureus (2024).
6. Health risks of prenatal and early-life microplastics exposure: a comprehensive review, Environment & Health (2025).
7. Li et al., Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation, Nature Food (2020), and the researchers’ advice for parents (Trinity College Dublin).
8. Ragusa et al., Raman microspectroscopy detection and characterisation of microplastics in human breastmilk, Polymers (2022).
9. Agency for Toxic Substances and Disease Registry, Breastfeeding and PFAS (2024), for the CDC and AAP advice to keep breastfeeding despite environmental contaminants.
10. Bisphenol A and phthalates in diet: an emerging link with pregnancy complications, Nutrients (2020).
11. Qian et al., nanoplastics in bottled water, Proceedings of the National Academy of Sciences (2024).