High concentrations of three common forms of phthalates in men have been shown to impact fertility compared to men without high concentrations of the chemicals, according to a recent study by the NIH and colleagues. The results were published online in Fertility and Sterility.

Prior to excretion, phthalates are frequently broken down in the body and chemically altered. Between 2005–2009, 501 couples from the Longitudinal Investigation of Fertility and the Environment (LIFE) study not being treated for infertility but trying to achieve pregnancy were interviewed. They underwent anthropometric assessments and supplied urine specimens for evaluation of the presence of 14 phthalates and Bisphenol A (BPA). Couples were assessed until there was a positive human-chorionic gonadotropin pregnancy test or 12 menstrual cycles without conception.

RELATED: OB/GYN Resource Center

Findings showed that high concentrations of monomethyl phthalate, mono-butyl phthalate, and monobenzyl phthalate in males were associated with a 20% increase in the time it took for the couples to conceive. BPA concentration was not associated with rates of pregnancy in males or females.

Germaine M. Buck Louis, PhD, lead author of the article, points out that these results would not have emerged if only one of the partners had been evaluated for environmental effects and pregnancy. Earlier studies have shown that high concentrations of some phthalates can negatively impact sperm mobility and count, as well as create semen abnormalities.

For more information call (301) 496-4000 or visit NIH.gov