Children born to women who have been exposed to bisphenol A (BPA) during pregnancy, especially during the first trimester, may be at greater risk of developing asthma, according to a study presented May 1 at the Pediatric Academic Societies (PAS) annual meeting in Denver.

In their study of 367 pairs of mothers and infants, researchers from the Penn State College of Medicine measured BPA levels in the urine of the pregnant women at 16 and 26 weeks’ gestation, as well as after delivery. Nearly all the women had detectable BPA in their urine at some point during pregnancy. 

Every six months for three years, the mothers were asked whether their child had asthma symptoms. At 6 months of age, infants whose mothers tested for high levels of BPA during pregnancy were twice as likely to wheeze as babies whose mothers tested for low levels of BPA. However, no differences in wheezing rates were found by 3 years of age.

Researchers also found that high BPA levels detected in women at 16 weeks’ gestation were associated with wheeze in their offspring, but high levels at 26 weeks’ gestation and birth were not, a possible indication that timing of BPA exposure in pregnancy may be more significant than the level of exposure.

“Consumers need more information about the chemicals in the products they purchase so they can make informed decisions,” said Dr. Adam Spanier, lead author of the study. “Additional research is needed in this area to determine if changes should be made in public policy to reduce exposure to this chemical.”

Until more information is available, Dr. Spanier recommended, women of child-bearing age should consider avoiding products made with BPA.

The study has not been peer-reviewed yet. The abstract is available here.

BPA has been used for more than 40 years in the manufacture of many hard plastic food containers and the lining of metal food and beverage cans. Trace amounts of the chemical can be found in some foods packaged in these containers, and the chemical is detectable in over 90 percent of the U.S. population.

Last year, a study published in the journal Environmental Health Perspectives found that the offspring of female mice exposed to BPA showed significant signs of asthma. Although the scientists said more research needed to be done, they speculated that BPA’s status as an “environmental estrogen” may set off allergic response-inducing chemicals such as histamine and a sudden release of allergy-promoting substances.

The Food and Drug Administration has said it has concerns that BPA might affect the brain, behavior and prostate gland in fetuses, infants and children. Although there has been no federal regulatory action taken against BPA in the United States, some individual states have banned its use in products used by children.  Canada has declared BPA a toxic substance   and the European Union has banned its use in baby bottles.

Reacting to consumer demand, several major manufacturers are removing it from products. Last week, however, Coca-Cola shareholders voted 994 million to 332 million in rejecting a proposal that the soft drink company develop alternatives to BPA in its can linings.