While several studies have linked BPA to behavioral problems in children, this report is the first to suggest that a young girl’s emotional well-being is linked to her mother’s exposure during pregnancy rather than the child’s exposure after birth. Girls were more sensitive to the chemical in the womb than boys, maybe because BPA mimics the female hormone estrogen, which is thought to play a role in behavioral development.
The results add to a growing body of research that suggests exposure to BPA poses health risks in humans. While the federal government has long maintained that low doses of BPA are safe, the Food and Drug Administration and other federal agencies are taking a closer look and investing in more research about the chemical’s health effects.
In the Cincinnati study, the authors cautioned that their results could have been skewed by the eating habits of the mothers observed. For more than 40 years, BPA has been used to make plastic bottles and the lining of metal-based cans. It’s possible that mothers who ate a lot of packaged foods simply didn’t eat enough nutrients essential for brain development, said Joe M. Braun, the study’s lead author.
None of the children exhibited behavior outside the normal range, said Braun, a research fellow at the Harvard School of Public Health. But they behaved worse than children whose mothers had relatively low traces of BPA in their urine, he said.
The results were based on urine samples from the mother (two during pregnancy and one at birth) and urine samples from their children taken at ages 1, 2 and 3. The mothers then filled out surveys about their children’s behavior at age 3.
The American Chemistry Council, which represents the chemical industry, dismissed the study, saying it has “significant shortcomings” in design and its conclusions “are of unknown relevance to public health.”
The group cited the study’s small sample size as one drawback. Braun said it’s difficult to conduct this type of research with a larger group.
Several experts who track the issue said they would like to see the study repeated with another group of children.
Linda Birnbaum, director of the National Institute of Environmental Health Sciences, said the sample size is reasonable and its results support studies that show similar effects in animals. The challenge with observational studies such as this one, she said, is that the effects are subtle and, therefore, tougher to tease out.
“These are not the kinds of effects that hit you over the head,” Birnbaum said. “We’re not looking for missing arms and legs.”
Birnbaum’s group and the Environmental Protection Agency funded the study.
Meanwhile, she said, the marketplace has spoken.
Due to consumer pressure, some companies have voluntarily removed the chemical from products or started offering BPA-free alternatives. A number of states and cities, including Maryland, have banned BPA in some children’s products. France has taken action to prohibit BPA use in food packages altogether, but the ban has not yet taken effect.
Earlier this month, the American Chemistry Council petitioned the FDA to ban the use of the chemical in baby bottles and sippy cups. The group said the chemical hasn’t been used in those products for years, but that the ban would help clear consumer confusion. The council maintains that BPA is safe.