Can microplastics in the placenta affect a baby's birth weight and size?

What's actually in it

Microplastics from food packaging, water bottles, synthetic clothing, and cosmetics enter a pregnant person's bloodstream and reach the placenta. Researchers have now confirmed that these tiny plastic particles don't just pass through. They embed themselves in placental tissue, where they sit for the duration of pregnancy.

The placenta is the baby's lifeline, providing oxygen, nutrients, and waste removal. Anything that interferes with its function can affect how well the baby grows.

What the research says

A 2026 cross-sectional study in Environ Int measured microplastic concentrations in human placentas and compared them with birth anthropometrics, the measurements taken at birth like weight, length, and head circumference.

Placentas with higher microplastic levels produced babies with lower birth weight, shorter length, and smaller head circumference. The most common plastic types found were polyethylene (from packaging) and polypropylene (from food containers and bottle caps).

The researchers believe microplastics interfere with placental function in several ways. They may block nutrient transfer across the placental barrier, trigger local inflammation that reduces blood flow, and disrupt hormones produced by the placenta that regulate fetal growth.

Lower birth weight is one of the strongest predictors of health problems in childhood and beyond. Reducing microplastic exposure during pregnancy by using glass containers, stainless steel bottles, and avoiding plastic-wrapped foods is a reasonable precaution.