Researchers have suggested that exposure to common environmental chemical BPA (Bisphenol-A) could be a factor as to why some infertile couples have difficulty conceiving.
Dr Catherine Racowsky, PhD, director of the Assisted Reproductive Technologies Laboratory at Brigham and Women's Hospital (BWH), said that 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 randomized trial examined 352 eggs from 121 consenting patients at a fertility clinic. The eggs, which would have otherwise been discarded, were exposed to varying levels (20 ng/ml, 200 ng/ml and 20 micro g/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:
1. A decrease in the percentage of eggs that matured.
2. An increase in the percentage of eggs that degenerated.
3. 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 chromosomes 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.
The study has been published online in the journal Human Reproduction.
