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More Bad News about BPA and Fertility
Oh, that bisphenol A (BPA) — the common plastic chemical that is linked to infertility. Now there's more bad news from a new mouse study out of the University of Cincinnati and published in the March Journal of Toxicology . Researchers found that BPA — an industrial chemical and environmental pollutant found in many hard plastic products — affected mice's ability to reproduce by altering the structure of the uterus in a way that could lead to a potentially fatal infection called pyometra.
Pyometra, an Infection and inflammation of the uterus, is most often seen in animals such as dogs and cats, but can also affect humans. The condition is a result of hormonal and structural changes in the uterus lining, which can be caused by chronic exposure to estrogens. The researchers investigated whether estrogenic endocrine disruptors, such as bisphenol A, can cause pyometra. To do this, they exposed some mice to different dietary doses of BPA in their food, ranging from 4 to more than 4,000 micrograms per kilogram of body weight per day, and they exposed some mice to 17(a)-ethinyl estradiol (EE), a semi-synthetic steroidal estrogen, in doses of 1 to greater than 150 micrograms per kilogram of body weight per day. A control group of mice received no dose of BPA or EE.
"Using two different strains of mouse models, we monitored to see which doses of endocrine disruptors affected which strains,” says Scott M. Belcher, PhD, Professor of Pharmacology and Cell Biophysics, and lead investigator on the study. "In a commonly used strain of mice, C57BL/6, pyometra occurred with 15 micrograms per kilogram of body weight per day of EE and 33 micrograms per kilogram of body weight per day of the BPA treatment groups.”
Dr. Belcher says it is difficult to extrapolate these finding to humans. "The exposures used, where pyometra was observed, are higher than is believe to be observed in humans," he says. "However the pathologies observed reflect that BPA can act on the uterus and the immune system as an estrogen endocrine disruptor. The difference in sensitivity to the actions of BPA and ethinyl estradiol demonstrate there are genetic differences that impact the sensitivity to estrogens and endocrine disruptors, which suggest that in humans there could also be a large individual variation in the sensitivity to exposures of endocrine disrupting chemicals."
Of course, this is not the first study to find problems with BPA and its impact on your health and fertility. The chemical has been linked to such things as:
- problems with sperm quality and quantity
- reduction in normal fertilization of eggs when they were retrieved for in vitro fertilization (IVF)
- alterations in the gene expressions of reproductive organs
The chemical has also been linked to other health problems, such as heart disease, developmental abnormalities. and thyroid problems. In 2008, the first large study in humans found that people with the highest BPA levels in their urine were more than twice as likely to have heart disease or diabetes than those with the lowest levels.
On Thursday, March 22, the Natural Resources Defense Council, which filed a lawsuit against the Food and Drug Administration in 2008 after the agency did not respond to the group’s petition to ban the chemical in light of new research, renewed pressure on the FDA to respond to the group's petition to ban BPA. The FDA has until March 31 to respond to the petition.
How can you reduce your exposure to BPA? Most people receive the majority of their exposure in food and drink packaging, e.g., water and infant bottles, compact discs, impact-resistant safety equipment and medical devices. So try to limit your exposure to these things as much as possible.