Are microplastics in breast milk harmful to newborns?

What's actually in it

Breast milk is not just food. It is a complex mix of nutrients and microbes that help build a baby's immune system. However, recent science shows that this process is being interrupted by polystyrene microplastics. These are tiny plastic particles that end up in the body and can move into breast milk.

Beyond plastic particles, breast milk can also contain other chemical contaminants. Research has identified phthalates (chemicals used to make plastic soft) and DINCH metabolites in breast milk, as noted in a 2026 study in Ecotoxicol Environ Saf. We are also seeing perfluoroalkyl compounds (often called forever chemicals) and organophosphate esters (flame retardants) appearing in breast milk samples, according to a 2026 study in Sci Rep and a 2026 study in J Agric Food Chem.

What the research says

A 2026 study in FASEB J found that polystyrene microplastics disrupt the natural transfer of healthy bacteria from mother to baby. This process is known as vertical transmission. When this transfer is blocked, it impairs the baby's early gut health and immune system development.

The presence of these materials is a systemic issue. Research into packaged milk products, published in a 2026 study in Food Chem Toxicol, highlights how widespread plastic contamination has become in our food supply. Because these chemicals and particles are now common in the environment, they are increasingly being detected in the biological systems of nursing mothers.