Research Highlight: BPA linked to infertility in women

woman with water crpBPA (Bisphenol-A) is a  chemical compound found in many consumer products including polycarbonate plastics and epoxy resins used in food and drink packaging.  However, evidence is accumulating that suggests that BPA may contribute to a variety of health problems. Because BPA has been shown to alter the function of the endocrine system, and has been detected in blood and urine of patients undergoing treatment for infertility, researchers suspect that it may interfere in some way with the normal reproductive cycle.

In an NIEHS Center funded pilot study, a group of researchers led by Center member Catherine Racowsky, asked the question, “Does exposure to bisphenol-A (BPA) impact fertility by affecting the maturation of human oocytes (eggs)?”

They conducted a randomized trial, using 352 clinically discarded oocytes from 121 patients undergoing infertility treatment at the Brigham and Women’s Hospital, exposing the oocytes to increasing levels of BPA in the laboratory.

They found that exposure to BPA caused a variety of problems with the normal development and maturation process of the eggs, leading to  a reduction in  the number of eggs that matured, and an increase in the number that degenerated or underwent abnormal activation.

Of the eggs that did mature, there was a significant trend toward malformation of the spindles, a structural part of the egg that is critically important for the proper alignment and separation of the chromosomes.

The investigators explained that “If the chromosomes do not separate correctly, then the egg will end up with either too many or too few chromosomes — in which case, generally speaking, if the egg fertilizes it will give rise to an embryo that isn’t capable of developing, or if it develops it will give rise to a chromosomally abnormal individual.”

These preliminary observations document for the first time the effect of BPA on oocyte meiotic maturation, spindle morphology and chromosome alignment in human oocytes. Taken together with a growing body of evidence regarding the negative health effects of BPA, this work brings us one step closer to understanding the impact of chemicals in our  environment on the growing problem of human infertility.

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Read the whole paper here

Ronit Machtinger, Catherine M.h. Combelles, Stacey A. Missmer, Katharine F. Correia, Paige Williams, Russ Hauser, and Catherine Racowsky. Bisphenol-A and human oocyte maturation in vitro. Human Reproduction, 2013 DOI: 10.1093/humrep/det312