Doctors are unable to explain the cause of infertility for as many as 20% of US couples that are unable to conceive due to infertility issues. However, a new study conducted by Catherine Racowsky, director of the Assisted Reproductive Technologies Laboratory at Brigham and Women's Hospital (BWH), which was published online in the scientific journal Human Reproduction (July 31, 2013) reveals that exposure to Bisphenol-A (BPA) could very likely be the cause of many of these unexplained infertility cases.

“To our knowledge, this is the first study that has shown that BPA has a direct effect on egg maturation in humans,” said Dr. Racowsky. “Because exposure to BPA is so ubiquitous, patients and medical professionals should be aware that BPA may cause a significant disruption to the fundamentals of the human reproductive process and may play a role in unexplained infertility.”

Images of eggs examined in this study show a properly formed spindle structure with aligned chromosomes (image A) and eggs with spindles of various abnormal shapes and misaligned chromosomes after being exposed to BPA (images B, C, D and E). The green images on the left are the eggs' spindle, the red center images are the eggs' chromosomes and the images on the right show the spindles and chromosomes merged together. Credit: Brigham and Women's Hospital

The trial examined a random sample of 352 eggs obtained from 121 patients visiting a fertility clinic. All participating donors consented to their eggs, which would in any event have been discarded, being used in the trials. The eggs were exposed to various levels of BPA (20 ng/ml, 200 ng/ml and 20 µg/ml) in a controlled laboratory environment. One egg from each participant was not subjected to BPA exposure – this egg served as the control. The research team then examined the eggs to assess the effect of BPA exposure. They found that BPA exposure resulted in a decrease in the number of eggs that matured; an increase in the number of eggs that degenerated; and an increase in the incidence of spontaneous activation – an abnormal process where an egg behaves like it has been fertilized, when in fact it hasn't. As the dosages of BPA were increased, so too was the likelihood of degeneration or spontaneous activation, while the likelihood of maturity decreased as the dosage levels increased. Furthermore, as the dosage of BPA was increased, there was a decrease in the number of eggs that exhibited bipolar spindles and correctly aligned chromosomes among the eggs that reached maturity, which mirrors similar studies conducted on animal eggs.

“Our data show that BPA exposure can dramatically inhibit egg maturation and adds to a growing body of evidence about the impact of BPA on human health. I would encourage further research to gain a greater understanding of the role BPA plays in infertility,” said Racowsky. BPA is found in everyday items including till slips, tin cans and plastic bottles, including bottled water and soft drink bottles. The latter is particularly worrisome, as BPA can leach into the contents, which we then ingest as we drink the bottled water or soft drinks contained within.

Once it is ingested into our system, this chemical can be very destructive and cause various health issues, including infertility according to the above study. In order to avoid exposure, quench your thirst by drinking filtered water from a glass, or top off a non-plastic or BPA-free water bottle with filtered water. Not only is this better for your health, it is better for the environment too!

Journal Reference: 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