07 Nov 2017

Pregnant women exposed to common toxin have lower levels of hormone crucial for brain development

Pregnant women exposed to higher levels of a common environmental pollutant, perchlorate, had lower levels of a thyroid hormone crucial for normal foetal brain development, according to a study presented at the Society for Endocrinology annual conference in Harrogate. These findings suggest that exposure to this common chemical should be minimised in pregnant women to prevent potential neurodevelopmental abnormalities in children.

Perchlorate is a common environmental pollutant found in water, milk, some foods and everyday chemicals, including fertilisers and air bags. Perchlorate is known to reduce absorption of iodine from the blood into the thyroid, where iodine is needed to make the thyroid hormone, T4. Since T4 is essential for normal foetal brain development, this suggests that perchlorate exposure could decrease maternal thyroid hormone levels, which may lead to brain development defects in babies.

In order to investigate the impact of perchlorate exposure on maternal thyroid hormone levels, Professor Bijay Vaidya and his team measured the levels of perchlorate in urine samples and thyroid hormone levels in blood samples from healthy, pregnant women. The team found that higher perchlorate levels were associated with lower levels of thyroid hormones. These data were gathered in the South West of England but mirror data reported from other parts of the world.

Prof Vaidya comments, “This study adds to the growing body of evidence that exposure to the environmental pollutant, perchlorate, is widespread and may have deleterious health outcomes.”

Although further studies are required to confirm that perchlorate exposure in pregnant women can lead to impaired neurological development in offspring, these findings suggest that public health initiatives should be put in place to reduce perchlorate exposure, particularly in vulnerable populations, such as pregnant women. Furthermore, the possible health impacts of perchlorate exposure on the healthy population remain uncertain and should also be investigated.

Prof Vaidya concludes, “These findings are important because we know that optimum thyroid hormone levels during pregnancy are essential for normal foetal brain development, and this study shows that this common pollutant may be adversely affecting brain development in children.”