Plastics Chemical BPA May Harm Human Fertility
However, experts say lab findings might not translate to real-life risk
By Steven Reinberg
WEDNESDAY, July 31 (HealthDay News) -- A chemical used in everything from food-can linings to store receipts might also pose some risk for infertility and birth defects, a new study suggests.
Exposure to bisphenol A, or BPA, may disrupt the human reproductive process and play a role in about 20 percent of unexplained infertility, said researchers from Harvard University.
In laboratory experiments, they exposed 352 eggs from 121 consenting patients at a fertility clinic to varying levels of BPA.
"Exposure of eggs to BPA decreased the percentage of eggs that matured and increased the percentage of eggs that degenerated," said lead researcher Catherine Racowsky, director of the assisted reproductive technologies laboratory at Brigham and Women's Hospital in Boston.
BPA also increased the number of eggs that underwent an abnormal process called "spontaneous activation" that makes eggs act as if they have been fertilized when in fact they haven't been, Racowsky said.
Moreover, many eggs exposed to BPA that matured did so abnormally, increasing the odds for infertility and birth defects such as Down syndrome, she said.
Eggs exposed to the highest levels of BPA were the most likely to show these ill effects, the researchers found. Their results are similar to earlier research examining the effect of BPA on animal eggs, they said.
Racowsky cautioned that these latest results with human eggs were seen in the laboratory, so whether BPA exposure works the same way in real life isn't known. And the research also found only an association between BPA and infertility and birth defects, not necessarily a cause-and-effect link.
In addition, the eggs used in the experiment were going to be discarded because they didn't respond normally and thus could be considered damaged to begin with, she said.
BPA is known to disrupt the hormonal system, with the chemical acting like an artificial estrogen. "There are many ways it can disrupt the hormonal system," Racowsky said.
The chemical is all throughout the environment, Racowsky said, and it's almost impossible to avoid exposure to it. "People need to be aware of the toxins in the environment and try to lead the healthiest life they can possibly lead," she said.
The report was published online July 31 in the journal Human Reproduction.
Dr. Avner Hershlag, chief of the Center for Human Reproduction at North Shore University Hospital in Manhasset, N.Y., agreed that a laboratory finding does not necessarily mean the same effect will be seen in the real world.
"When you make a leap from the lab to patients you have to examine a whole different model," said Hershlag, who was not involved with the study. "To say from [the results] that this might explain part of unexplained infertility is a bit of a stretch. Unexplained infertility remains unexplained."