Can UV filter chemicals in sunscreen affect a baby's brain development during pregnancy?

What's actually in it

Chemical sunscreens use UV filters like oxybenzone, octinoxate, homosalate, and avobenzone to absorb ultraviolet light before it damages your skin. These chemicals don't just sit on the surface. They absorb through the skin into your bloodstream within hours of application.

During pregnancy, UV filters cross the placenta and reach the developing baby. They've been detected in amniotic fluid, cord blood, and breast milk.

What the research says

A 2026 review in Environ Int examined studies on prenatal UV filter exposure and children's cognitive and neurobehavioral development. The review found links between higher maternal UV filter levels and changes in children's behavior and learning abilities.

Several UV filters act as endocrine disruptors, particularly mimicking or blocking thyroid hormones. Thyroid hormones are essential for fetal brain development, controlling the timing of brain cell growth, migration, and wiring. When these hormones are disrupted during pregnancy, the effects show up as attention problems, lower cognitive scores, and behavioral changes in early childhood.

Oxybenzone (BP-3) was the UV filter with the strongest evidence of neurodevelopmental effects. It was also the most commonly detected in pregnant women's blood.

Sun protection during pregnancy is still important. But you can switch to mineral sunscreens that use zinc oxide or titanium dioxide instead. These sit on top of the skin and don't absorb into the bloodstream.