I came across two articles recently (1.and 2. below) about an environmental contaminant, bisphenol-A, that can cause subtle behavioral changes in offspring when ingested during pregnancy. The articles reported on the same study, but chose somewhat different remarks to report from the researchers.
For this study, urine samples were taken from 249 pregnant women at 16 and 26 weeks of pregnancy, and BPA levels were measured in their urine. When the children were 2 years old, their behavior was assessed with the Behavioral Assessment System for Children-2 (BASC-2).
The study of BPA exposure was published in Environmental Health Perspectives online on Oct 6, 2009, by researchers at Simon Fraser University, University of North Carolina, and Cincinnati Children's hospital.
Exposed girls may act more like boys
The researchers reported that daughters of women with higher levels of BPA in their urine during early preganancy were more likely to have aggressive and hyperactive behaviors than daughers of women with lower BPA levels. "In other words, girls whose mothers had higher BPA exposure were more likely to act like boys than girls whose mothers has lower BPA levels, especially if the exposure was seen earlier in pregancy, " said doctoral student Joe Braun, one of the study's lead authors, at the UNC School of Global Public Health.
Male offspring exposed to BPA in utero became more anxious and withdrawn than unexposed male offspring.
Early pregnancies most vulnerable
The higher the levels of BPA during mom's first 16 weeks of pregnancy, the more likely her child was to later show behavior somewhat atypical of his or her gender on the BASC-2 test. High levels of BPA in mom's urine later than 16 weeks showed no link to behavior.
Behavioral changes in the most highly exposed babies averaged 2 to 6 points higher on the BASC-2 test (on a 100-point scale) for each 10-fold increase in mom's early urinary BPA values, Braun reports. Said researcher Lamphear, "the magnitude of these changes is similar to the subtle IQ drops attributable to environmental lead exposures in U.S. children."
The team has continued to study the children who are now 3 to 5 years old.
The cause for the changes are not known. But there have been growing concerns about BPA exposure for years, said Braun. Earlier studies have shown the same effects in the offspring of mice exposed to high BPA levels during pregnancy. The changes have persisted beyond infancy in the mice.
BPA is used to make polycarbonate plastics and epoxy resins that are found in some kinds of plastic bottles, canned food linings, water supply pipes and medical tubing. According to the Centers for Disease Control and Prevention, about 93% of people in the U.S. have detectable levels of BPA in their urine. More than 99% of the pregnant women in the study tested positive for BPA in at least one of the urine tests, usually in the low parts-per-million range.
Canada has banned BPA in baby bottles
"Canada has bannned BPA in baby bottles and other baby products but that may not be sufficient to protect children. Although this is the first study of its kind, it suggests that we may also need to reduce exposures during pregnancy," said Dr. Bruce Lanphear, professor of children's environmental health in the Faculty of Health Sciences at Simon Fraser University and one of the study's lead authors.
Cash register receipts may be the biggest source of contamination
Janet Ratloff writing for Science News noted: Early data from the Warner Babcock Institute for Green Chemistry point to cash register and credit card receipts as "potentially rich sources of BPA. Spot checks typically turn up between 60 and 100 milligrams of BPA per receipt, well avove the nanogram values that have been measured leaching from polycarbonate plastic foodware". Says scientist John Warner," The biggest [BPA] exposures in my opinion, will be those cash register receipts."
Alternative sources for "canned" tomatoes
I read elsewhere this week the comments of Fredrick Vom Saal, PhD, an endocrinologist at the University of Missouri who studies bisphenol-A. He says: "You can get 50 mcg of BPA per liter out of a tomato can, and that's a level that is going to impact people, especially the young. I won't go near canned tomatoes." One solution to the canned tomatoes is to buy tomatoes in glass bottles, which don't need resin linings, such as Bionature and Coluccio. Also available are Tetra Pak boxes such as Trader Joe's and Pomi.
1. Patric Lane. "Prenatal exposure to BPA might explain aggressive behavior in some 2-year-old girls." UNC News. October 6, 2009. http://uncnews.unc.edu/conctent/view/2944/1/ Patric Lane can be reached at 919.962.8596 or at email@example.com
2. Janet Ratloff. "BPA in womb linked to childhood behavior. Found for exposure during first 16 weeks of pregnancy." Science News. November 7, 2009.
3. Joe Braun and Bruce Lanphear. Environmental Health Perspectives online. October 6, 2009.
Researcher contact info:
Braun can be reached at firstname.lastname@example.org or at 919.951.8519. Lanphear can be reached at email@example.com or at 778.387.3939. UNC's Gillings School of Global Public Health contact is Ramona DuBose at firstname.lastname@example.org or 919.966.7467.
Key words:: BPA bisphenol-A pregnancy contaminants