Public concern about bisphenol-A has grown in recent years, with research showing that the chemical — used in the manufacture of hard, clear plastics — has the potential to disrupt the body’s hormonal system.
A report issued in 2008 by the U.S. Department of Health and Human Services’ National Toxicology Program cited “some concern” for the neural and behavioral effects of BPA in fetuses, infants and children “at current human exposures.” Animal studies have found that BPA accelerates puberty and poses a cancer risk, and other studies have tied the chemical to an increased risk of heart disease and diabetes in adults.
A new study by a University at Albany-led research team has joined this chorus.
The team found that exposure to BPA alters the hormonal response of women undergoing in vitro fertilization, a process by which egg cells are fertilized by sperm outside of the body.
“Couples undergoing IVF might want to avoid BPA,” said Michael Bloom, the study’s first author and an assistant professor in the departments of Environmental Health Sciences and Epidemiology and Biostatistics at the University at Albany School of Public Health.
Bisphenol-A is used primarily in the production of polycarbonate plastics and epoxy resins, and can be found in a variety of common products, such as water bottles and baby bottles, the linings of canned foods and store receipts.
In a study published earlier this month in the scientific journal Fertility and Sterility, the University at Albany-led research team identified a link between BPA exposure and a reduction in peak estrogen concentrations among women undergoing in-vitro fertilization. According to the researchers, reduced estrogen concentrations can adversely influence the quality of egg-containing follicles, which could make it harder for a woman to conceive through IVF.
“At this point, what we’re showing is that BPA appears to be interfering with the endocrine feedback necessary for a successful IVF cycle,” said Michael Bloom, the study’s first author and an assistant professor in the departments of Environmental Health Sciences and Epidemiology and Biostatistics at the University at Albany School of Public Health.
Bloom said the research was conducted over the course of five years, at a reproductive health clinic at the University of California, San Francisco, which partnered with the University at Albany on the study.
Forty-four women undergoing IVF participated in the study. They provided blood specimens on the day their eggs were retrieved for insemination, and these specimens were measured for BPA.
During IVF, an increase in estrogen in response to stimulating medicines is critical to ensuring the harvesting of healthy eggs. The study found that each doubling of the concentration of BPA in a woman’s blood specimen was associated with a nine to ten percent decrease in peak-estrogen value, after adjusting for factors such as race and smoking.
Estrogen is the primary female sex hormone, and its presence in the body typically increases during pregnancy. Bloom described estrogen as a marker that shows that a woman is responding to stimulating drugs during IVF. “If you don’t experience an increase in estrogen, it means the drugs aren’t working,” he said.
Bloom said it is unclear what the team’s findings mean for women who are trying to become pregnant, but are not undergoing in vitro fertilization.
“That’s the $64,000 question,” he said.
The concentrations of BPA measured in the study were among the highest reported to date in blood specimens, Bloom said. But he added that very few studies have looked specifically at BPA levels in blood.
Bloom noted that the women who participated in the study were fasting, which means there should have been little to no BPA in their systems. But he said research has shown there are other sources of BPA exposure besides dietary sources; BPA, he said, appears to be able to go through the skin.
Bloom noted that the women who participated in the study were “not in a normal metabolic state. They were loaded up with many drugs.” He said it’s possible these drugs affected the women’s ability to clear BPA from their bodies.
In 2010, Bloom’s research team found that exposure to BPA could compromise the quality of a woman’s eggs retrieved for in vitro fertilization.
‘Time to remove bpa’
Environmental groups have been sounding the alarm about the dangers of BPA for years.
“BPA is an incredibly widely used chemical,” said Sonya Lunder, a senior analyst at the Washington, D.C.-based Environmental Working Group. “It’s found in a reasonable quantity in all people.”
Lunder said environmental groups are not particularly concerned about the presence of BPA in products that are unlikely to result in elevated levels of the chemical in the body, such as eyeglasses and bicycle helmets.
“We’re honing in on where the chemical poses the greatest risk,” she said. “We think it’s time to remove BPA from food storage plastic, receipts, canned linings.”
Steven Hentges, of the American Chemistry Council’s Polycarbonate/BPA Global Group, said that scientific studies show that exposure to BPA from all food and consumer products “are minute and well below safety standards set by government regulatory bodies around the world, and that BPA is not accumulated in the body and is rapidly eliminated.”
Hentges criticized the new University at Albany study.
“As noted by the authors, this is a preliminary study that is limited by its small size,” he said. “More importantly, the BPA measurements in this study are inconsistent with findings from multiple recent high quality studies, which suggests these measurements are not likely to be valid. Because of these limitations, the results of this study will need to be confirmed in a larger scale study that corrects the deficiencies of this limited study before they can be accepted as valid.”