CHICAGO – Exposure to BPA before birth could affect girls’ behavior at age 3, according to the latest study on potential health effects of the widespread chemical.

Preschool-aged girls whose mothers had relatively high urine levels of bisphenol-A during pregnancy scored worse than other young girls, but still within a normal range, on behavior measures that included anxiety and hyperactivity.

The results are not conclusive and experts not involved in the study said factors other than BPA might explain the results. The researchers acknowledge that “considerable debate” remains about whether BPA is harmful, but say their findings should prompt additional research.

In Maine, the Legislature approved a ban on the chemical in April, and it became law without Gov. Paul LePage’s signature.

In February, LePage created national headlines when he joked that, at worst, BPA exposure caused women to grow “little beards” and expressed skepticism of science linking BPA, a synthetic hormone, to health problems in children.

In the most recent study, the researchers measured BPA in 244 Cincinnati-area mothers’ urine twice during pregnancy and at childbirth. The women evaluated their children at age 3 using standard behavior questionnaires.

Nearly all women had measurable BPA levels, like most Americans. But increasingly high urine levels during pregnancy were linked with increasingly worse behavior in their daughters. Boys’ behavior did not seem to be affected.

The researchers said if BPA can cause behavior changes, that could pose academic and social problems for girls already at risk for those difficulties.

“These subtle shifts can actually have very dramatic implications at the population level,” said Joe Braun, the lead author and a research fellow at Harvard’s School of Public Health.

For every 10-fold increase in mothers’ BPA levels, girls scored at least six points worse on the questionnaires.

The study was released online today in Pediatrics.

Linda Birnbaum, director of the National Institute of Environmental Health Sciences and the National Toxicology Program, said the study contributes important new evidence to “a growing database which suggests that BPA exposure can be associated with effects on human health.”

Grants from that federal agency helped pay for the study.

The Food and Drug Administration has said that low-level BPA exposure appears to be safe. But the agency also says that because of recent scientific evidence, it has some concern about potential effects of BPA on the brain and behavior in fetuses, infants and small children. The FDA is continuing to study BPA exposure and supports efforts to minimize use in food containers.

BPA has many uses, and is found in some plastic bottles and coatings in metal food cans. It was widely used in plastic baby bottles and sippy cups, but industry phased out that use.

Braun said it’s possible that exposure to BPA during pregnancy interferes with fetal brain development, a theory suggested in other studies.

The researchers evaluated other possible influences on children’s behavior, including family income, education level and whether mothers were married, and still found an apparent link to BPA.