Scientists Raise More BPA Concerns

Scientists at Tufts University School of Medicine have published a study that raises new concern about the effects of the ever-present chemical bisphenol A (BPA), especially the effect on pregnant women.

"Mice exposed to BPA in the womb and during nursing subsequently had fewer successful pregnancies and delivered fewer pups over the course of the study," reported one of the study's co-senior authors, Ana M. Soto, MD, professor of anatomy and cellular biology at Tufts University School of Medicine (TUSM) and member of the cell, molecular and developmental biology program faculty at the Sackler School of Graduate Biomedical Sciences.

The study may add ammunition to those who want BPA banned. Sen. Diane Feinstein (D-CA) pushed to ban BPA in infant bottles and Sippy cups, as part of the recently passed Food Safety and Modernization Bill. Her amendment provoked such strong food industry opposition that the measure did not pass until she dropped that provision.

BPA is a chemical added to plastic to make it rigid. Though it is slowly being phased out, it has had widespread use in beverage bottles and food containers. Recent studies have found that the chemical is present in many consumers' bodies.

Decreased fertility

In the Tufts study, fertility decreased over time in female mice that had been exposed during fetal and neonatal (perinatal) development to doses of BPA that were lower than or equal to human environmental exposure levels.

At the highest of three doses tested, only 60 percent of the BPA-exposed mice had four or more deliveries over a 32-week period, compared with 95 percent in the unexposed control group. Decline of the reproductive capacity of the female mice in this study was not obvious at first pregnancy, when the animals were very young, but manifested later in life with a decline in number of pups born per delivery.

"This finding is important because standard tests of reproductive toxicology currently consist of assessing the success of a first pregnancy in young animals. If subsequent pregnancies are not examined, relevant effects may be missed," said co-senior author Beverly S. Rubin, PhD, associate professor of anatomy and cellular biology at TUSM and member of the cell, molecular and developmental biology and neuroscience program faculties at the Sackler School.

The authors say their findings are potentially of great relevance to humans because BPA is used in the production of materials people are exposed to every day, such as polycarbonate plastics and the resins used to coat the inside of food and beverage cans.

The scientist say BPA has effects that mimic those of estrogen, a natural hormone. Fetal and neonatal exposure to BPA has been shown to have other hormone-related effects in rodents, including increased risk of mammary and prostate cancers, altered behavior, and obesity.

BPA has been found in the urine of over 92 percent of Americans tested, with higher levels in children and adolescents relative to adults. It has also been detected in human maternal and fetal plasma, the authors said.

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