Fluoride exposure and thyroid hormone levels in pregnancy: The MIREC cohort.

Hall M, Hornung R, Chevrier J, Ayotte P, Lanphear B, Till C. Environ Int. 2024 Jan 12;184:108442. doi: 10.1016/j.envint.2024.108442

Question: Is exposure to fluoride during pregnancy associated with maternal thyroid hormone levels in the MIREC study?

What did the researchers do:
Researchers measured fluoride concentrations in drinking water and in spot urine samples collected at each trimester for 1876 women in the MIREC study. They also measured maternal thyroid hormone levels in first trimester blood samples. Researchers then estimated associations between maternal fluoride exposure and thyroid hormone levels, with consideration for fetal sex.

What did they find:
Increases in urinary fluoride levels were associated with increased TSH (Thyroid Stimulating Hormone) concentrations among women pregnant with female fetuses, but not male fetuses.

What does this mean:
The findings from this study suggest that higher levels of fluoride exposure in pregnancy may have adverse effects on maternal thyroid function. The implications of this work are of public health significance when considering the vital role of the maternal thyroid in supporting optimal fetal growth and neurodevelopment. Future research in this area is needed to see whether these results will be replicated in other populations.

Back to list