A new study suggests that exposure to bisphenol A (BPA)—a chemical found in hard plastics, receipts, and many canned food linings—may raise the risk of miscarriage, at least for women who already have fertility problems. While the study is far from definitive, it adds to a growing debate over how chemicals in everyday products affect reproductive health.
Researchers from Stanford and elsewhere analyzed BPA levels in blood samples from 114 women in early pregnancy who had a history of infertility or miscarriage. Sixty-eight of those women eventually miscarried. The women with the highest concentrations of BPA in their blood had an 80 percent higher chance of miscarrying than those with the lowest BPA concentrations.
The small study has not yet been peer-reviewed, and it suggests an association, not a direct causal relationship, between BPA and miscarriages. But the researchers urged that more testing is needed. Linda Giudice, president of the American Society for Reproductive Medicine, said the study adds to the “biological plausibility” that BPA might affect fertility.
“It’s not just one study,” Tracey Woodruff, director of University of California San Francisco’s program on reproductive health and the environment, told Rewire. “There are more studies that have looked at this issue. … They’re all extremely suggestive of potential effects of BPA on fertility.” Other such studies, Woodruff said, include work from the University of California San Francisco on in vitro fertilization as well as research on mouse ovaries.
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Woodruff said that even though the study is small and the risk ratio modest, it could still be cause for concern. “Everyone is exposed, so if you have a lot of exposure, even if you have a modest risk you can still have a lot of affected people,” she said. Most people have some BPA in their urine.
BPA is known as an endocrine disruptor, in that it mimics estrogen and could interfere with our hormonal systems. The Food and Drug Administration banned the use of BPA in baby bottles and sippy cups in 2012, although it claims that current levels of human exposure are low and easily metabolized enough not to cause concern. People seeking to limit their exposure to BPA can avoid microwaving or pouring hot liquids into plastic containers, for instance.
Many manufacturers have already voluntarily phased the chemical out of polycarbonate products like Nalgene bottles, but some advocates say this may not be enough.
“It just means that manufacturers have replaced BPA with other plasticizers, and we don’t know if they’re toxic; we can only guess,” Sara Alcid, programs and policy associate with the Reproductive Health Technologies Project, told Rewire. In many cases, BPA has been replaced with BPS, another endocrine-disrupting chemical.
Chemical regulation in the United States hasn’t been updated since the Toxic Substances Control Act of 1976, although a new bill seeks to rectify that. Of the roughly 80,000 consumer chemicals used in commerce, the Environmental Protection Agency has tested only 200 but regulated only five. Reproductive problems have dramatically increased over the last three decades, and the American College of Obstetricians and Gynecologists recently issued a joint opinion with the American Society for Reproductive Medicine on the threat of toxic chemicals to reproductive health.
“I think [BPA] is a chemical we have to look into more, but I don’t think it’s the most important chemical risk out there,” said Woodruff.