Heavy Metals in Pregnancy Disrupt Newborn Thyroid Function

Heavy metals crossing the placenta are disrupting thyroid function in newborns. The thyroid runs brain development. If it's off at birth, the effects can be permanent.

What the Study Found

A 2026 study in Environment International measured maternal-fetal metal levels and the placental transfer efficiency of heavy metals, then examined how they affect neonatal thyroid function. Higher metal transfer to the fetus was associated with disrupted thyroid hormone levels at birth.

The study also found that maternal vitamin D levels played a protective role. Women with higher vitamin D had babies with better-protected thyroid function, even with metal exposure.

Where Heavy Metals Come From

Lead, mercury, cadmium, and arsenic are in contaminated water, rice, seafood, cosmetics, and air pollution. They cross the placenta and concentrate in the fetus.

What You Can Do

Test your water for heavy metals. Choose low-mercury fish. Avoid cosmetics with heavy metals (some imported cosmetics contain lead). Talk to your doctor about vitamin D supplementation during pregnancy.

Check out our non-toxic baby products for safer pregnancy essentials.

Also see glass food storage for safer alternatives.

Source: Prenatal Metals and Thyroid Study (2026). Environ Int.