Can phthalate exposure during pregnancy reduce a child's fluid intelligence?

What's actually in it

Phthalates are used as plasticizers in PVC plastic, as solvents in fragrances, and as carriers in personal care products. They enter the body through food contact with flexible plastic packaging, scented personal care products, and household dust. During pregnancy, they cross the placenta and reach the developing brain.

Fluid intelligence is the ability to reason, solve new problems, and think flexibly, separate from learned knowledge. It depends on the prefrontal cortex and the neural connections built during brain development. Phthalates disrupt thyroid hormones that control the timing of these connections forming.

What the research says

A 2026 study in Neurotoxicol Teratol used latent variable modeling to measure the combined burden of multiple phthalates during pregnancy and link that burden to children's fluid cognition scores. Higher combined phthalate exposure during pregnancy predicted lower fluid intelligence scores in the children assessed.

The study used latent variable modeling specifically to capture the real-world scenario: pregnant people are exposed to multiple phthalates simultaneously, not just one. The combined burden shows a stronger signal than any single phthalate alone, because the chemicals act through similar pathways and their effects add together.

Fluid intelligence predicts academic performance, problem-solving ability, and long-term cognitive outcomes. Unlike acquired knowledge, it's hard to remediate once the developmental window closes.

The highest-impact phthalate sources during pregnancy are fragrance products (perfume, scented lotion, hair products, air fresheners) and flexible vinyl products (shower curtains, vinyl flooring, some plastic food packaging). Switching to fragrance-free personal care products addresses the largest contributor.