Narrator: This is Science Today. Normal thyroid function is essential to the healthy growth and cognitive development of fetuses and children. So, when a University of California, Berkeley, study linked bisphenol A, or BPA, to thyroid hormone changes in pregnant women, it added to the growing health concerns about the chemical, which is found in many hard plastics and the lining of tin cans. Research epidemiologist Jonathan Chevrier says there was an interesting additional finding in their study.
Chevrier: We measured BPA twice during pregnancy and we tried to look at the relationship based on the time that had elapsed between the measurement of thyroid hormone and the time that BPA was measured. The idea was, can we figure out whether the exposure to BPA has a long-term effect on the thyroid hormone or is it really a transient effect?
Narrator: Chevrier says the good news is the effect was not permanent, but ...
Chevrier: The bad news is that we're at this point constantly exposed to BPA — 95 percent of the U.S. population has detectable levels of BPA in their urine.
Narrator: For Science Today, I'm Larissa Branin.