Exposure in the womb to bisphenol-A, a chemical used to make some plastic containers, may cause behavior and emotional problems in young girls, a study found.
The research showed that hyperactive, anxious, aggressive and depressed behavior was more common in 3-year-old girls who were exposed in the womb to bisphenol-A than in boys of the same age. No association was seen between bisphenol-A levels during later childhood and behavior for either gender, according to the study released today by the journal Pediatrics.
Bisphenol-A, or BPA, has been linked to male infertility, diabetes and cancer. Today’s findings confirm two previous studies finding that prenatal contact with BPA affects behavior and is the first to show that fetal exposure may be more important than coming into contact with the chemical during childhood, said Joe Braun, the lead study author.
“The developing fetus is tremendously sensitive to the affects of BPA,” said Linda Birnbaum, director of the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The institute is part of the U.S. National Institutes of Health, which partly funded the study.
“It was the mother’s exposure that was the critical window,” Birnbaum, who wasn’t an author on the paper, said in an Oct. 21 telephone interview. “That suggests that a pregnant woman, if she can, be careful of what she’s exposed to because it might have consequences to her children.”
BPA is used to harden plastic and make canned food watertight and for decades was included in the manufacture of plastic food containers and baby bottles. The U.S. Environmental Protection Agency said in September it would conduct tests on the chemical to review its effects on the environment. The agency said it was continuing to work with the Food and Drug Administration and the Centers for Disease Control and Prevention to examine how BPA affects human health.
The chemical mimics the female hormone estrogen and may be causing girls to be exposed to a hormone they typically aren’t exposed to in the womb, said Braun, a research fellow in the Department of Environmental Health at the Harvard School of Public Health in Boston, in an Oct. 21 telephone interview. He said more studies are needed to determine why the behavior problems were found only in girls.
The study doesn’t support recent government research that shows the way BPA is processed in the body makes it unlikely the chemical could cause health effects at any “realistic exposure level,” said Steven G. Hentges of the American Chemistry Council, a Washington-based industry trade group.
‘Shortcomings in Design’
“The study released in Pediatrics has significant shortcomings in study design and the conclusions are of unknown relevance to public health,” Hentges said in an Oct. 21 e-mail. “The researchers themselves acknowledge that it had statistical deficiencies, including its small sample size and the potential for the results being due to chance alone.”
The researchers took urine samples to measure BPA in 244 mothers and their children. The mothers’ samples were tested during pregnancy and at birth. The children were tested for the chemical each year from ages 1 to 3. The women also filled out surveys about their children’s behavior at age 3.
BPA was detected in more than 85 percent of the urine samples from the mothers and more than 96 percent of the samples from the children. As the chemical levels increased, so did behavior problems in the girls, the study showed.
“As the mother’s concentration of BPA rose, the girls born to those mothers had higher scores on these behavior problem indices,” said Braun. “If pregnant women or parents are concerned about exposure to BPA, they can try to reduce it by limiting their exposure to canned foods and packaged foods.”
None of the children in the study had behavior classified as abnormal, he said.
John M. Rost, chairman of the North American Metal Packaging Alliance, a Washington-based trade group, said checking BPA levels through urine at intermittent times has been shown to have “little meaning to overall daily intake.”
“The statistical relevance of the findings are questionable at best, Rost said Oct. 21 in an e-mail. ‘‘This type of data mining study has been shown to be susceptible with errors.’’
The researchers plan to follow the children through ages 8 or 9 to see if the behavioral issues persist, he said. The study also was funded in part by the EPA.