Prenatal exposure to two endocrine disruptors associated with behavioral disorders in children

A study by Inserm, in collaboration with the CNRS, the University of Grenoble Alpes (UGA), the Grenoble Alpes University Hospital (CHU), and the Barcelona Institute for Global Health (ISGlobal), published on December 10 in the The Lancet Planetary Health journal, suggests there may be an association between exposure in the third trimester of pregnancy to two synthetic phenols, methylparaben and bisphenol S, commonly found in everyday products (food, cosmetics, plastics, etc.), and questionnaire scores that could suggest behavioral disorders in children. Further studies will be needed to confirm these results and better understand the mechanisms involved.

With neurodevelopmental disorder diagnose in children on the rise, the role of environmental factors is increasingly being examined. These include chemicals such as endocrine disruptors found in many everyday products, such as certain phenolic compounds and parabens. However, establishing a causal relationship for each substance remains complex and the mechanisms underlying these effects are still poorly understood.

A study bringing together researchers from Inserm, in collaboration with the CNRS, the University of Grenoble Alpes (UGA),  the Grenoble Alpes University Hospital (CHU), and the Barcelona Institute for Global Health (ISGlobal)[1], published on December 9 in The Lancet Planetary Health journal, suggests a potential  association between questionnaire scores that could suggest behavioral disorders in children and prenatal exposure to two chemicals : bisphenol S, a known endocrine disruptor, and methylparaben (a preservative used in cosmetics and food products, among other things), which is under assessment as endocrine disrupting by the European Chemicals Agency..

“This is particularly worrying because bisphenol S is used as a substitute for bisphenol A, which has been banned for certain uses, such as food containers. However, more and more studies suggest adverse health effects, even as we are increasingly exposed to this substance,” explains Claire Philippat, a researcher at Inserm and the last author of this study.

These results are based on two key cohorts for studying the effect of chemical pollutants on children’s health: the first, consisting of 1,080 mothers and their children recruited in Barcelona  between 2018 and 2021, and the second, consisting of 484 mothers and their children recruited in the Grenoble region between 2014 and 2017.

The research team looked at the consequences of exposure to 12 substances suspected or recognized as endocrine disruptors by health authorities during pregnancy: bisphenols, parabens, and other phenolic compounds such as triclosan, measured via repeated urine samples.

“This is one of the strengths of these cohorts: the women collected up to 42 samples during pregnancy, whereas previous studies had a maximum of three. This allows for a real improvement in the measurement of exposure to these substances,” explains the researcher.

After birth, the children’s behavior was assessed between 18 months and two years of age using the Child Behavior Checklist (CBCL), a questionnaire completed by one of the parents to screen for possible behavioral disorders, such as attention difficulties or anxious, depressive, or aggressive behaviors.

The results suggestthat exposure to methylparaben in the third trimester of pregnancy was associated with higher scores on this questionnaire, suggesting possible behavioral disorders in children. Similarly, exposure to bisphenol S, a known endocrine disruptor, during the same period was linked to high scores, but only in boys. However, no cocktail effect resulting from the mixture of different phenols was observed.

To understand the mechanisms by which these compounds could affect children’s behavior, the researchers explored the hypothesis that the hypothalamic-pituitary-adrenal (HPA) axis, whose role is, among other things, to regulate the body’s response to stress, might be involved. They measured the concentrations of several key hormones in this system (cortisol, cortisone, dehydrocorticosterone) in hair samples taken from mothers at the end of pregnancy. However, the hormonal variations observed did not explain the link between prenatal exposure to pollutants and behavioral disorders in children.

“Our results are not sufficient to rule out this hypothesis, as there are still very few studies on the subject. But it is possible that other biological mechanisms, such as disruption of the thyroid or estrogen axis, may be involved” explains the researcher.

Further research will be needed to better understand the mechanisms at play. “Although several studies suggest a link between exposure to endocrine disruptors and behavioral disorders, little research has focused on bisphenol S and methylparaben, the latter of which is not officially recognized as an endocrine disruptor, but only suspected. It is therefore essential to continue conducting studies on large cohorts, with rigorous measurements of exposure to pollutants, in order to better understand these effects,” concludes the last author.

Bibliography:
Prenatal phenol exposure and child behavior: insights into the hypothalamic-pituitary-adrenal axis from two prospective mother-child cohorts
Lancet Planetary Health, 10 december 2025. doi.org/10.1016/ j.lanplh.2025.101330

[1] This study was funded by ANSES, the Fondation de France, and the European ATHLETE (Advancing Tools for Human Early Lifecourse Exposome Research and Translation) fund, which aims to better understand and prevent health effects of numerous environmental hazards and their mixtures, starting from the earliest stages of life.