Researchers from Inserm and Grenoble Alpes University, in collaboration with the CNRS, the CHU Grenoble Alpes, and the University of Granada (Spain), investigated the impact of exposure to these chemical substances during pregnancy on children's cognitive development. The findings, published in Environmental Health Perspectives, indicate an association between exposure to certain phthalates and a bisphenol in the third trimester of pregnancy and children's IQ scores at three years old.
Phthalates and phenols are families of chemicals widely present in the environment, used as additives in plastics or as preservatives. Some are suspected or proven endocrine disruptors capable of altering hormonal function, potentially impacting health during fetal life and early childhood.
The study followed a cohort of 380 mothers and their children. Scientists measured exposure markers to 26 phthalates and phenols, including bisphenols and parabens, using repeated urine samples collected during pregnancy. This methodology allowed for a more precise assessment of exposures than previous studies. Children's IQ was evaluated using a standardized test by a neuropsychologist.
Researchers observed negative associations between exposure to a mixture of six priority substances (identified by prior work as potentially harmful, including DEHP, DEP, DnBP, DiBP, and bisphenols A and S) in the third trimester of pregnancy and children's IQ scores. On average, an increase in exposure to this mixture was associated with a 2.86-point decrease in IQ.
« A few IQ points less might seem small for an individual child, but at the population level, it translates to more children facing difficulties », explains Claire Philippat, an Inserm researcher and the study's last author. She notes that these substances are not highly persistent and are therefore good targets for prevention, for example, by reducing the use of cosmetics or limiting food packaged in plastic, especially when heated. However, regulation remains the most effective measure.
