phthalates and infertility

A clinical study reported in the journal Human Reproduction has investigated whether phthalates are associated with semen quality.


Phthalates are a group of chemicals that are added to plastics to make them softer and more flexible. They can be found in plastic products, children’s toys, and some cosmetics.

Results from basic research have indicated that high doses of phthalates in rats act as anti-androgens, inhibiting the effects of the male hormones. In addition, clinical studies of infertile men have linked low semen quality with phthalates.

A group of researchers therefore investigated this association in a population of men who, together with their partners, were attempting to become pregnant. Urine samples from the men in the study were analyzed for metabolites of phthalates, while sperm quality was also assessed, which included measures of motility, morphology, sperm head size, and sperm chromatin structure.

Urinary phthalate metabolites were found to be significantly associated with lower sperm count, lower sperm concentration, and a reduction in sperm quality. In terms of both sperm quality and quantity, the researchers report reductions are associated with phthalate metabolites present in the urine of the participants. However, the researchers also state that while these associations exist, there is not yet data available to help answer whether phthalates are associated with fertility. They therefore suggest that this should be an area of future research.


Bloom, MS, Whitcomb, BW, Chen, Z, Ye, A, Kannan, K, Buck Louis, GM. “Associations between urinary phthalate concentrations and semen quality parameters in a general population” Human Reproduction Published online: September 7, 2015. doi: 10.1093/humrep/dev219






Written by Deborah Tallarigo, PhD

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