Endocrine disruptors threaten the semen quality

The study has established a link between poor semen quality in adult men and their mothers’ occupational exposure to endocrine disruptors during pregnancy.

Endocrine disruptors, sometimes also referred to as hormonally active agents, endocrine-disrupting chemicals can interfere with endocrine (or hormonal) systems. These chemicals are linked with developmental, reproductive, brain, immune, and other problems.

It is generally found in many everyday products, including some plastic bottles and containers, liners of metal food cans, detergents, flame retardants, food, toys, cosmetics, and pesticides—the chemicals cause adverse effects in animals. But limited scientific information exists on potential health problems in humans.

Sexual differentiation, development, and proper functioning of the reproductive system are largely dependent on steroid hormones. Some animal studies show that exposure to EDCs during pregnancy can influence the development of the male reproductive system and sperm production and semen quality in adulthood.

A new study by the Epidemiologists from the Institut de recherche en santé, Environnement et travail (IRSET, Rennes, France), in collaboration with the UNIGE team, tends to determine the potential impact of endocrine disruptors on semen quality of men whose mothers were working at the early stages of their pregnancy.

The results show that men who have been exposed in utero to products known to contain endocrine disruptors are twice more likely to have semen volume and total sperm count per ejaculation below the reference values set by the WHO.

For the study, scientists evaluated the semen quality of around 3000 conscripts, 1045 out of which had their mother working during pregnancy. Through this analysis, scientists determined the semen volume, its concentration, motility, and morphology.

Serge Nef, professor at the Department of Genetic Medicine and Development of the UNIGE Faculty of Medicine, said, “A detailed questionnaire was also sent to the parents before the semen analysis was carried out, covering in particular the maternal jobs exerted during the conscripts’ pregnancy period.”

Luc Multigner, research director at the IRSET, said, “This allowed for the analysis of semen parameters of men whose mothers were employed during their pregnancy. The maternal jobs were classified according to the International Classification of Occupations (ISCO-88 of the International Labour Office of the WHO). Exposure to products containing endocrine disruptors during pregnancy has been defined using a job-exposure matrix, which makes it possible to attribute the maternal exposure a probability score.”

“This has enabled us to establish probabilities of exposure to one or more categories of products that may contain endocrine disruptors according to the mother’s occupation.”

Ronan Garlantézec said, “The results of this study show that young men exposed in utero to endocrine disruptors are twice as likely to have values below the reference values established by the WHO, both in terms of the semen volume (threshold at 2 ml) and the total number of spermatozoa per ejaculation (40 million). In our study, the products most associated with these anomalies were pesticides, phthalates and heavy metals.”

Serge Nef continues, “These observations do not determine the future fertility of young men, and only a follow-up over time will make it possible to assess the consequences. Nevertheless, the results could explain, at least in part, the low semen quality of some young Swiss men.”

Luc Multigner said, “The results of this study suggest an association between the mother’s occupational exposure to endocrine disruptors and a decrease in several semen parameters in their children during adulthood. It therefore appears necessary to inform women planning to conceive and during their early stages of pregnancy of the potential hazards of exposure to these substances, which could alter their children’s fertility.”

Ronan Garlantézec said“Similarly, it would be interesting to carry out a similar study in women, to evaluate the impact of endocrine disruptors is the same on the female reproductive system, although this is much more complex to carry out.”

Journal Reference:
  1. M Istvan et al. Maternal occupational exposure to endocrine-disrupting chemicals during pregnancy and semen parameters in adulthood: results of a nationwide cross-sectional study among Swiss conscripts. DOI: 10.1093/humrep/deab034

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