A very recently published study carried out by CNRS flags that exposure to endocrine disrupting chemicals (EDCs) causes changes in thyroid hormone signalling, which may disturb brain development. Frog embryos were exposed to a mixture of 15 chemicals commonly present in the fluid of a human mother’s womb.

The results of the study demonstrate that a short exposure to the mixture (3 days) affected thryoid hormone signalling, but also altered brain gene expression, reduced neuron volume and inhibited tadpole movement. Furthermore, these findings can be placed in the context of recent epidemiological studies showing that small variations in maternal thyroid hormone during early pregnancy impact children’s IQ.

Professor Barbara Demeneix, an author of the paper and work package leader in EDC-MixRisk, says:

“Undisturbed thyroid signalling is essential for normal brain development in all vertebrates. Since thyroid hormone is exactly the same in frogs and humans, these findings should prompt rapid action to remove these harmful chemicals from the market.”


The results are published by Nature in a peer-reviewed paper in Scientific Reports entitled “Human amniotic fluid contaminants alter thyroid hormone signalling and early brain development in Xenopus embryos”. The full article is available here.