Common Chemical Affects Thyroid Levels in Mothers and Sons


Researchers at the University of California, Berkeley have concluded that the estrogen-like compound Bisphenol A (BPA) can be linked to changes in thyroid hormone levels in pregnant women and in newborn baby boys.

The study appears in the journal Environmental Health Perspectives.

The thyroid is crucial to healthy fetus and childhood development. This is the first study to show negative effects from BPA exposure to thyroid hormones.

Granted, BPA has been in the sights of several environmental groups for some time now. BPA is a chemical found in hard plastics, canned food linings, dental sealants, and even sales receipts printed on thermal paper.

BPA was banned by the U.S. Food and Drug Administration in baby bottles and cups this past summer. The ban was almost unnecessary since the industry has done so voluntarily for many years.

Researchers analyzed BPA levels in urine samples from 335 women during the second half of pregnancy as well as thyroid hormone levels in blood samples taken from the mothers during pregnancy and from the newborns within a few days of birth. All the women were among the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, led by UC Berkeley professor of epidemiology and of maternal and child health Brenda Eskenazi.

"Most of the women and newborns in our study had thyroid hormone levels within a normal range, but when we consider the impact of these results at a population level, we get concerned about a shift in the distribution that would affect those on the borderline," said one of the study's authors. "In addition, studies suggest that small changes in thyroid level, even if they're within normal limits, may still have a cognitive effect."

"More than 90 percent of women of reproductive age have detectable levels of BPA in their urine, and some 97 percent of U.S. residents have detectable levels of the flame retardant PBDE (polybrominated diphenyl ether) in their blood," said senior author Kim Harley, adjunct associate professor of public health and associate director of CERCH. "Until we learn more about the human health effects of these chemicals, it would make sense to be cautious and avoid exposure when possible, particularly for those who are pregnant."

Source: Medical News Today


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