BPA Exposure and Infertility in WomenKatlyn Joy |25, September 2014
In July 2012, the Food and Drug Administration banned the use of BPA or bisphenol-A in products such as sippy cups and baby bottles because of concerns about the chemical's effect on young children and infant's development.
Previous studies have linked BPA to a laundry list of problems: reproductive and nervous systems of the young, aggressive and hyperactive behavior in girls born to mothers with highest levels of BPA, and behavioral problems such as anxiety and depression in children exposed to BPA.
In the mid-20th century, BPA became widely used in manufacturing, in plastics, in linings of canned goods, in register receipts and in many other products that 90 percent of Americans have BPA in their urine.
While a smoking gun, definitive study has not been done that has convinced the FDA to entirely ban or set safe levels for the chemical, enough has been uncovered to raise significant concern in the scientific and medical communities.
The FDA is performing its own studies and research, while the chemical makers deny the negative effects other groups believe BPA causes. Unfortunately, no good substitute has been found to replace BPA, which primarily hardens plastics and lines substances such as cans to prevent contamination.
According to an article in the New York Times, Dr. Jodi Flaws, a bioscientist at University of Illinois, has been studying the effects of BPA on a very specific are — the ovaries and related reproductive functions.
Over a month, Dr. Flaws exposed mice to BPA solutions the same amount as human exposure at a normal level would equal. She then tested the mice's ovaries, follicles where the eggs are located. The results were immediate and obvious. The follicles of the mice were fewer and smaller. The sex hormone, estradiol was not being produced at normal levels, and this seems to interfere with proper follicle development.
In spring 2014, further studies in Dr. Flaws' lab found that mice exposed to the BPA solution also stopped producing eggs that were viable at a premature early age.
Other studies have found similar results in species from sheep to primates, monkeys to man. The research points to one major health effect with BPA exposure, reproductive function and development in females. It appears the chemical could impair female fertility and shorten the reproductive years of a woman.
While many studies looking at the results of BPA exposure are inconclusive, scientists are narrowing down to one result that seems definite.
"But on this question of ovarian toxicity, all the studies are starting to line up," said Tracey Woodruff, the director of the program on reproductive health and the environment at the University of California, San Francisco.
It is possible that BPA exposure alone is not the culprit, as lifestyle, genetics and exposure to other toxins may play a role, or interact with one another.
Patricia Hunt, a Washington State University professor of genetics studied BPA in pregnant rhesus monkeys during the last two months of their gestation, to see how the chemical affected the ovaries. They only exposed the monkeys to the amount an average US adult would be exposed to. In both the second and third trimesters, the follicles and the germ cells that develop into eggs, or oocytes, were impacted. What Hunt and her team discovered was consistent with the rodent studies, and points to a strong likelihood that humans are similarly affected.
Harvard University researchers looked at data from IVF or in-vitro fertilization clinics to see how BPA affects follicles. Up to 80 percent of the women at the clinics tested for BPA, and the higher the amount, the fewer follicles found. When looking even closer, testing the follicular fluid in 357 discarded oocytes, the researchers saw link between higher BPA levels and more chromosomal abnormalities and stunted oocytes.
Dr. Hunt remarked, "Together with prior animal studies, the data support the negative influences of BPA on oocyte maturation."
However, providing conclusive evidence showing the exact impact of BPA on female fertility will take more time and more research. More factors are involved, such as the later ages women are trying to get pregnant and the fact that human chromosomes are more likely than rodents to have abnormalities.
Dr. Woodruff recommends avoiding BPA whenever possible, but not overthinking it all yet.
"We're still figuring this out, and the burden is on us — researchers, health care providers, manufactures — to do that well," she advised.
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