Chemical BPA reported to cause birth defects and miscarriage

Robin Wulffson MD's picture
bpa, bisphenol, birth defects, miscarriage, obesity, chromosome damage
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Bisphenol (BPA) is an industrial chemical that is present in many hard plastic bottles as well as metal-based food and beverage cans since the 1960s. A new study conducted by researchers affiliated with Washington State University and the University of California, Davis has reported that ingestion of BPA is linked to a risk of birth defects and miscarriage. They published their findings on September 24 in the Proceedings of the National Academy of Sciences.

The study falls on the heels of another research paper published earlier this month that found an association between childhood obesity and BPA.

The researchers note that BPA is a chemical that can disrupt the endocrine system; widespread use of it in consumer products has resulted in nearly continuous human exposure. In rodents, low-dose exposures have been reported to adversely affect two distinct stages of oogenesis (egg production) in the developing ovary: the events of prophase at the onset of meiosis in the fetal ovary and the formation of follicles in the perinatal ovary. (Myosis a special type of cell division necessary for sexual reproduction. During meosis, the chromosomes undergo a recombination of genetic material from both parents.) Because these effects could influence the reproductive longevity and success of the exposed individual, the researchers conducted studies in the rhesus monkey to determine whether BPA induces similar disturbances in the developing primate ovary.

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The researchers note that their study has found ‘compelling’ evidence that BPA may negatively impact women’s reproductive systems and cause chromosome damage, birth defects and miscarriages. When pregnant monkeys were given either a single daily dose of BPA or low-level continuous doses (which was given to mimic exposure levels in humans) it led to changes in the cells that would become eggs in the developing fetus. Once the offspring were ready to reproduce themselves, the egg cells were not able to divide properly because the fertilized egg had the wrong number of chromosomes. This can cause various birth defects such as Down syndrome and can even lead to miscarriage.

In addition, in the monkeys that were continually exposed to BPA, the investigators found the fetal eggs were not packaged the right way in follicles, which is where they develop. The researchers explain that eggs must be packaged properly in order to grow, develop and mature. They note that the exposed monkeys would have significantly fewer eggs because a female is born with all the eggs she’s going to have. Therefore, the reproductive lifespan of the monkeys may be shortened.

BPA is a low-grade estrogen that until recently was found in certain plastic bottles. These bottles are typically marked with the number ‘7’ inside a recycling symbol. It is still found in the linings of aluminum cans and heat-activated cash register receipts. A 2003-2004 National Health and Nutrition Examination Survey (NHANES) found BPA exposure is “nearly ubiquitous” in the U.S. population, with 92.6 percent of people over the age of 6 having detectable levels of BPA in their urine. The chemical has also been associated with obesity, cardiovascular disease, diabetes, breast cancer, prostate cancer and neurological disorders. The Food and Drug Administration (FDA) recently banned BPA from sippy cups and baby bottles; however, it did not extend the ban to other products.

Reference: Proceedings of the National Academy of Sciences

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