Lead, Mercury, and PFAS Pass Directly Into Breast Milk

What's in a mother's blood ends up in her breast milk. A massive review of 48 studies across 25 countries confirms it for lead, mercury, and PFAS.

48 Studies, One Clear Pattern

Researchers reviewed all available evidence on how arsenic, cadmium, lead, mercury, and PFAS in pregnant or breastfeeding women's bodies relate to levels in breast milk, according to a 2026 systematic review in Environ Res.

The results: higher exposure to lead, mercury, PFOA, and PFOS during pregnancy or breastfeeding correlated directly with higher concentrations in breast milk. The correlations were strong: up to 0.88 for lead, 0.66 for mercury, 0.97 for PFOA, and 0.97 for PFOS.

Moderate to High Confidence

The evidence was rated moderate certainty for lead, PFOA, and PFOS. Mercury evidence was rated low. Arsenic and cadmium data was limited and inconclusive.

This means reducing a mother's exposure during pregnancy and breastfeeding could directly lower what the baby receives through milk.

What You Can Do

Filter drinking water during pregnancy and breastfeeding. Avoid nonstick cookware and stain-resistant products (PFAS sources). Skip high-mercury fish. Test old homes for lead paint. And explore non-toxic baby products for a safer start.

Also see glass food storage for safer alternatives.

Source: O'Connor LE, Uffelman CN, Thoerig RC, et al. (2026). Environ Res.