The CDC estimates that about 6 million women in the U.S. have trouble getting pregnant or maintaining a pregnancy. Many of these women turn to in vitro fertilization (IVF) to get pregnant. However a recent study of women undergoing IVF procedures found that bisphenol A (BPA) exposure cut their success rate by as much as half compared to women with little exposure to BPA.
This is the first study to find an association between failed egg implantation and BPA exposure in women using IVF. These findings confirm what has been observed in animal studies and support previous studies that link BPA to fertility problems in humans.
Researchers measured BPA concentrations in the urine of 137 women undergoing IVF treatment at Massachusetts General Hospital Fertility Center. The women were all of childbearing age (18-45) and were using their own eggs for the procedure. Detailed medical and lifestyle histories were also obtained.
The women were categorized into one of four groups based on the level of BPA in their urine. The researchers compared the chances of getting pregnant in women in the highest exposure group to women in the lowest exposure group.
Regardless of other factors such as the woman’s age, day of embryo transfer and specific IVF protocol followed, they found a clear association between implantation failure and higher BPA levels. Moreover, these effects occurred in women with BPA levels lower than those of like-aged women in the general population.
The association between BPA exposure and failed pregnancies was also more pronounced in women who were poor responders to IVF treatment. Those with higher levels of BPA were less likely to become pregnant. These women were generally older and more likely to have past IVF treatment cycle failures. They also had reduced number of eggs, lower average number of eggs retrieved and less response to ovarian stimulation.
Prior studies in humans report that BPA exposure is associated with recurrent miscarriages, quality and number of eggs retrieved during IVF treatment and peak hormone levels essential for a successful pregnancy.
Studying the effects of endocrine disruptors, like BPA, in couples trying to get pregnant naturally can be difficult. IVF allows researchers to study the earliest stages of pregnancy usually not observable in couples conceiving naturally. For example, Implantation failure, the reason for 75% of pregnancy loss, happens before a woman knows she’s pregnant.
For more information about the dangers of BPA, read: The Low Down on Bisphenol-A (BPA): The Facts You Need To Know.
Environmental Health News