BPA may affect sperm quality in couples seeking in vitro fertilization.
Knez L, R Kranvogl, BP Breznik, E Voncina, V Vlaisavljevic. 2013. Are urinary bisphenol A levels in men related to semen quality and embryo development after medically assisted reproduction? Fertility and Sterility. http://dx.doi.org/10.1016/j.fertnstert.2013.09.030.
Bisphenol A may influence semen quality in male partners of couples undergoing in vitro fertilization, according to a new study by researchers in Slovenia.
Few studies have investigated the association between BPA, a hormone-disrupting chemical, and semen quality in humans. However, some animal studies have shown adverse effects on male reproductive function.
Exposure to BPA is widespread. The compound is used to make hard plastics and also is found in the liners of canned foods and some receipts.
“Our results suggest that low environmental levels of BPA in male partners of subfertile couples may affect semen quality,” the researchers wrote.
In the study, 149 men undergoing in vitro fertilization with a female partner provided urine and semen samples to researchers.
BPA was detected in 98 percent of the urine samples tested, with an average concentration of 1.55 nanograms per milliliter. The researchers found a statistically significant association between an increase in urinary BPA concentration and lower total sperm count, sperm concentration and sperm vitality [a measure of live sperm in the semen].
When the men were divided into four groups based on their urinary BPA levels, those with the highest BPA levels in their urine had 72 percent live sperm compared with 79 percent for men with the lowest levels. Seventy-five percent live sperm or higher is considered normal.
The researchers also found a trend toward lower total sperm count and sperm concentration when they compared men with the highest BPA levels to men with the lowest levels. The findings, however, were not statistically significant and may have been due to chance.
No link was found between the men's BPA levels and embryo development after implantation.
In their analysis, the researchers accounted for variables such as smoking, alcohol consumption and obesity that have been shown to negatively impact male reproductive health.
A possible limitation of the study, the authors note, is that the association was found in men with low fertility, who may respond differently to BPA exposure than men in couples not seeking infertility treatment. “Susceptible men, with already impaired spermatogenesis, might be more prone to harmful effects compared with men with intact spermatogenesis when exposed to environmental BPA,” wrote the scientists from Slovenia's University Medical Centre Maribor and Environmental Protection Institute.