Bisphenol A (BPA), an estrogen-like compound that has drawn increased scrutiny in recent years, has been linked to changes in thyroid hormone levels in pregnant women and newborn boys, according to a new study released on October 7 by researchers at the University of California, Berkeley. BPA is a controversial chemical found in hard plastics, such as plastic bottles, the linings of canned food and beverages, dental sealants and thermal paper commonly used for sales receipts. BPA has already been linked to increased risk for cardiovascular disease, miscarriages, breast and prostate cancer and reproductive dysfunction. Normal thyroid function is essential to the healthy growth and cognitive development of fetuses and children. Yet, until this study in the journal Environmental Health Perspectives, little was known about the effects of BPA exposure on thyroid hormones in pregnant women and newborns. In July, the U.S. Food and Drug Administration officially banned the chemical in baby bottles and cups, something the industry began doing voluntarily in recent years in response to consumer concerns about the potential risks of BPA. This is the first study to show an association between BPA and thyroid hormone in pregnant women, according to the study's lead author, Kim Harley, an adjunct associate professor of public health at the University of California, Berkeley. Almost all (about 95 percent) of women of reproductive age have enough BPA in their urine to be detectable. BPA has also been found in placental tissue and amniotic fluid and is known to have estrogen-like activity. Although thyroid hormone levels fell within a normal range, higher levels of BPA exposure were associated with lower thyroid levels in both mothers and newborn boys, though not girls, the investigators found. It's not clear why the gender difference but one hypothesis, Harley said, “is that boys may be less able to detoxify BPA than girls.” Harley said this is the first of several studies on BPA scheduled to come out in the coming months. The next two studies will look at the effects of BPA on neurodevelopment in children and on obesity. Original article published on Examiner.com.