In October, Kaiser Permanente published a study showing how BPA may cause low sperm counts and decreased sperm motility in men, an early confirmation of animal studies that also showed a link. Now, scientists at the University of California-San Francisco are publishing the first evidence that Bisphenol A, the chemical used widely in such products as hard plastics, the lining of canned foods and the coating of sales receipts, may compromise the ability of human eggs, too.
Taken together, the two studies up the ante on Bisphenol A concerns, which already run the gamut from obesity to cancer, based primarily on worries that children exposed in the womb or shortly after birth will be affected by the chemical, which mimics estrogen.
The new study is small, though, so its results can't be taken as definitive.
The study, published in the Journal of Fertility and Sterility, looked at just 26 women part of a larger study of the effect of environmental contaminants on fertility. But it found that those women with twice as much BPA in their blood had half as many viable eggs for in vitro fertilization.
The study is consistent with some earlier research that found BPA levels associated with altered DNA in mouse eggs, and BPA urine concentrations associated with fewer eggs retrieved for in vitro fertilization.
BPA is only one of many chemicals that may affect fertility or early childhood development. An estimated 80,000 synthetic chemicals are in use in the United States, and most have never been tested for toxicity. Further, endocrine-disrupting chemicals like Bisphenol A, because they are thought to affect the body at minute levels, have escaped regulations that were designed when scientists were unanimous in believing that "the dose makes the poison" that if high doses showed no serious health effects, than low doses would not either.
Like many chemicals, BPA is found in the blood and urine of virtually every American tested by the Centers for Disease Control and Prevention.
"While preliminary, the data indicate the negative effect of BPA on reproductive health and the importance of allocating more funding to further investigate why such environmental contaminants might be disrupting fertility potential," said Dr. Victor Y. Fujimoto, MD, the study's lead author.
Because there is no BPA test available for couples trying to get pregnant, and no established concentrations that would identify high exposures, the researchers recommend limiting exposure to BPA and other chemicals that might affect reproduction. The University of California-San Francisco's Program on Reproductive Health publishes Toxic Matters to help couples avoid exposures to substances that might hurt fertility.
As for Bisphenol A, couples can avoid canned foods, avoid plastic with recycling symbols No. 3 and No. 7 and wash hands after handling money or sales receipts. Many manufacturers have removed BPA from water bottles, baby bottles and products for young children, and a handful of local laws restrict the use of BPA in baby and children's products but an effort to pass a national BPA ban on children's products failed as part of the recent food safety bill.
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