How mom's metal exposure affects baby's thyroid
The impact of prenatal maternal-fetal metal levels and placental transfer efficiency of metals on neonatal thyroid function: The modulatory role of maternal vitamin D levels in pregnancy.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Thallium, a rarely discussed metal, was the strongest maternal contributor to reduced FT4.
Thallium is not commonly tested for or regulated in pregnancy. Most public health focus is on lead or mercury—this study shows thallium may be far more potent in disrupting thyroid function.
Practical Takeaways
Pregnant women should get their vitamin D levels checked and supplement if deficient (aim for >30 ng/mL).
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Thallium, a rarely discussed metal, was the strongest maternal contributor to reduced FT4.
Thallium is not commonly tested for or regulated in pregnancy. Most public health focus is on lead or mercury—this study shows thallium may be far more potent in disrupting thyroid function.
Practical Takeaways
Pregnant women should get their vitamin D levels checked and supplement if deficient (aim for >30 ng/mL).
Publication
Journal
Environment international
Year
2025
Authors
Jixing Zhou, J. Tong, Chunmei Liang, Jie Sheng, Xiaoyan Wu, Guopeng Gao, Shuangqin Yan, Fangbiao Tao, Kun Huang
Related Content
Claims (6)
Higher levels of multiple metals in a mother’s blood and her baby’s umbilical cord blood are linked to lower levels of free thyroxine in newborns, which may indicate that exposure to metal mixtures affects fetal thyroid hormone levels more than exposure to single metals.
When pregnant individuals have low vitamin D levels, the harmful effects of mercury and iron crossing the placenta on the newborn's thyroid function may be stronger. Vitamin D levels might influence how the fetal thyroid responds to these metals.
When more of certain metals and minerals pass from mother to fetus through the placenta, newborns may have higher levels of thyroid-stimulating hormone and lower levels of free thyroxine, which are indicators of altered thyroid hormone regulation.
Higher levels of thallium and arsenic in mothers, higher copper levels in the umbilical cord, and less efficient transfer of copper from mother to fetus are linked to lower levels of free thyroxine in newborns, which may indicate these factors play a key role in disrupting fetal thyroid function.
How efficiently metals pass from a mother’s bloodstream through the placenta to the fetus is a better indicator of thyroid hormone disruption in newborns than the amount of metals present in the mother’s blood.