BPA changes DNA of mice offspring

NEW HAVEN, Conn., June 11 (UPI) -- Exposure during pregnancy to bisphenol A, found in many plastic household items, causes a genetic defect in the offspring of female mice, U.S. researchers say.

BPA is used to make hard polycarbonate plastic for baby bottles, refillable water bottles and food containers, as well as the linings of metal food cans.

"The big mystery is how does exposure to this estrogen-like substance during a brief period in pregnancy lead to a change in uterine function," study co-author Dr. Hugh Taylor of the Yale University School of Medicine in New Haven, Conn., says in a statement.

Taylor and colleagues injected pregnant mice with a low dose of BPA on pregnancy days 9-16. After the mice gave birth, the scientists analyzed the uterus of female offspring and extracted DNA.

The researchers found that BPA exposure during pregnancy had a lasting effect on one of the genes that is responsible for uterine development and subsequent fertility in both mice and humans -- HOXA10. These changes in the offspring's uterine DNA resulted in a permanent increase in estrogen sensitivity.

"We don't know what a safe level of BPA is, so pregnant women should avoid BPA exposure," Taylor says. "There is nothing to lose by avoiding items made with BPA -- and maybe a lot to gain."

The findings are scheduled to be presented at The Endocrine Society's 91st annual meeting in Washington.