Higher concentrations in the blood suggest higher exposures. They measured blood concentration of PFASs and thyroid function (TSH, T4, Free T4 index) in 732 pregnant women participating in a prospective study in Boston, MA known as Project Viva, at approximately 10 weeks of pregnancy. They also examined thyroid hormone (T4) levels in the blood from 480 newborn babies as part of the New England neonatal thyroid screening program. Higher levels of 4 of the 6 PFASs measured in the mothers were associated with lower free T4 index levels in pregnant women and lower thyroid hormone (T4) levels in male newborn babies. TSH levels in the mother were not affected by PFAS exposure in mothers except those with positive anti-thyroid peroxidase antibodies (a marker of auto-immune thyroid disease). These results indicate that environmental exposure to EDCs, specifically PFASs, during pregnancy can negatively impact thyroid function in both the mother and the newborn.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
These results suggest that exposure to PFASs in the environment can affect thyroid hormone levels in mothers and their babies. Higher measured blood concentrations of PFAS’s were associated with lower free T4 index in mothers and lower thyroid hormone levels in male newborns. This is concerning since thyroid hormone deficiency has been associated with negative effects on brain development. Additional research is needed to determine whether PFAS exposure during pregnancy can cause impairments in brain development of the baby related to alterations in thyroid function.
— Whitney W. Woodmansee MD