BPA exposure disrupts human egg maturation

July 31, 2013
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

As many as 20 percent of infertile couples in the United States have unexplained reasons for their infertility. Now, new research led by Catherine Racowsky, PhD, director of the Assisted Reproductive Technologies Laboratory at Brigham and Women's Hospital (BWH), shows that exposure to BPA (Bisphenol-A) could be a contributing factor as to why some infertile couples are having difficulty conceiving. The study will be published online on July 31, 2013 in the journal Human Reproduction.

"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."

The examined 352 eggs from 121 consenting patients at a . The eggs, which would have otherwise been discarded, were exposed to varying levels (20 ng/ml, 200 ng/ml and 20 µg/ml) of BPA in a laboratory setting. An egg from each patient was not exposed to BPA and served as the control. Researchers then examined the eggs and found that exposure to BPA caused:

  • A decrease in the percentage of eggs that matured.
  • An increase in the percentage of eggs that degenerated.
  • An increase in the percentage of eggs that underwent spontaneous activation, the abnormal process when an egg acts as though it has been fertilized, even though it has not been.

As the BPA dose increased, there was a decreased likelihood of maturity, an increased likelihood of degeneration and an increased likelihood of spontaneous activation. Additionally, among the mature eggs, there was a significant trend toward a decreased incidence of bipolar spindles and aligned with an increased dose of BPA. Researchers note that these results are similar to the previous research examining the impact of BPA exposure on animal eggs.

Racowsky said, "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."

Explore further: BPA lowers male fertility: report

More information: The full title of the paper is "Bisphenol-A and human oocyte maturation in vitro".

Related Stories

BPA lowers male fertility: report

June 6, 2011

Daily exposure to a chemical that is prevalent in the human environment, bisphenol A (BPA), causes lowered fertility in male mice, according to the results of a new study that will be presented Saturday at The Endocrine Society's ...

BPA affects sex-based behavior in mice

May 28, 2013

(Medical Xpress)—Bisphenol A (BPA) is a common chemical found in household plastics. Previous studies on rodents show that BPA exposure is associated with problems with brain and behavioral development. There is evidence ...

Recommended for you

We've all got a blind spot, but it can be shrunk

August 31, 2015

You've probably never noticed, but the human eye includes an unavoidable blind spot. That's because the optic nerve that sends visual signals to the brain must pass through the retina, which creates a hole in that light-sensitive ...

Biologists identify mechanisms of embryonic wound repair

August 31, 2015

It's like something out of a science-fiction movie - time-lapse photography showing how wounds in embryos of fruit flies heal themselves. The images are not only real; they shed light on ways to improve wound recovery in ...

New 'Tissue Velcro' could help repair damaged hearts

August 28, 2015

Engineers at the University of Toronto just made assembling functional heart tissue as easy as fastening your shoes. The team has created a biocompatible scaffold that allows sheets of beating heart cells to snap together ...

Fertilization discovery: Do sperm wield tiny harpoons?

August 26, 2015

Could the sperm harpoon the egg to facilitate fertilization? That's the intriguing possibility raised by the University of Virginia School of Medicine's discovery that a protein within the head of the sperm forms spiky filaments, ...

Research identifies protein that regulates body clock

August 26, 2015

New research into circadian rhythms by researchers at the University of Toronto Mississauga shows that the GRK2 protein plays a major role in regulating the body's internal clock and points the way to remedies for jet lag ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.