A new study adds to the growing concern that prenatal exposure to the chemical bisphenol A could harm children's development.
In the study of 249 pregnant women, the first to examine the effects of BPA on children's behavior, researchers found that girls whose mothers had the highest levels of BPA during pregnancy were more aggressive and hyperactive at age 2 than other girls. Findings appear today in the journal Environmental Health Perspectives.
Girls were more likely to be aggressive if their mothers had high levels of BPA -- an estrogen-like chemical used in many consumer products -- early in pregnancy or at about 16 weeks, the study says. A typical pregnancy lasts 40 weeks.
The girls had aggression scores that were similar to those of boys, as measured by a commonly used test, says co-author Joe Braun of the University of North Carolina-Chapel Hill. Boys appeared unaffected by BPA.
Braun says he plans to follow children until age 5, because behaviors can change over time.
Michelle Macias, a doctor and spokeswoman for the American Academy of Pediatrics, notes that the increases in aggression were subtle. "Nothing in this study suggests that these kids have higher rates of behavioral disorders," Macias says.
Pediatrician Lawrence Diller, who specializes in treating hyperactivity, notes that many other factors could have caused the girls' aggressive behavior. Scientists need to perform a more comprehensive study before sounding "alarm bells" about BPA, he says. A Food and Drug Administration report on BPA's safety is expected to be finished next month.
Based largely on animal experiments, the government's National Toxicology Program last year expressed "some concern" about BPA's effects on the brain, behavior and prostate gland in children before and after birth.
Hugh Taylor, an obstetrician/gynecologist at Yale University School of Medicine, notes that the new findings closely match the animal studies.
And Taylor says the study raises concerns about the effect of exposing a fetus to an artificial substance that mimics estrogen. Although estrogen is often considered a "female hormone," it actually helps to "masculinize" the male brain around the 11th and 12th weeks of pregnancy, says neurobiologist Louann Brizendine, author of The Female Brain.
"In the developing brain, timing is everything," Brizendine says. "I'm worried that tiny amounts of this stuff, given at just the wrong time, could partly masculinize the female brain."
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