Endocrine disruptors threatens semen quality
Scientists from UNIGE and IRSET have established a link between poor semen quality in adult men and their mothers鈥� occupational exposure to endocrine disruptors during pregnancy.
Endocrine disruptors, such as certain pesticides, heavy metals and phthalates, are associated with poorer sperm quality in men in adulthood, if the mother was exposed to them during pregnancy. 漏 UNIGE
A growing number of studies show that the environmental factors and lifestyle habits of pregnant women play an important role in the health of their child. But how about the semen quality of young men? Researchers at the AV短视频 (UNIGE), Switzerland, showed two years ago that only 38% of Swiss men had semne parameters above the thresholds set by the World Health Organisation (WHO) for fertile men. Epidemiologists from the Institut de recherche en sant茅, environnement et travail (IRSET, Rennes, France), in collaboration with the UNIGE team analyzed the potential impact of endocrine disruptors on听 semen quality of men whose mothers were working at the early stages of their pregnancy. Their results, published in the journal Human Reproduction, 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.
Endocrine disrupters are chemical substances of natural or synthetic origin which can interfere with the endocrine system and causes adverse health effects in an organism, or its progeny, according to the World Health Organization (WHO). 鈥淪everal animal studies have already shown that gestational exposure to certain endocrine disruptors can influence the development of the male reproductive system, as well as the sperm production and semen quality in adulthood,鈥� explains Ronan Garlant茅zec, a researcher at the IRSET, the Rennes AV短视频 Hospital Centre (CHU) and AV短视频 of Rennes 1. 鈥淚n view of the results obtained by听 Serge Nef鈥檚 team on the semen听 quality of young Swiss men, we were interested in studying the potential effect of exposure to endocrine disruptors during pregnancy as one out of many possible reasons behind the observed trends鈥�, he continues.
The semen of more than 1000 conscripts analysed
The team of Serge Nef, professor at the Department of Genetic Medicine and Development of the UNIGE Faculty of Medicine, has evaluated semen quality of around 3000 conscripts, 1045 out of which had their mother working during pregnancy. 鈥淔or each of them, a semen quality analysis was carried out to determine the semen volume, as well as the sperm concentration, motility and morphology,鈥� explains the Serge Nef. 鈥淎 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鈥� pregnancy period.鈥�
This allowed for the analysis of semen parameters of men whose mothers were employed during their pregnancy. 鈥淭he maternal jobs were classified according to the International Classification of Occupations (ISCO-88 of the International Labour Office of the WHO),鈥� explains Luc Multigner, research director at the IRSET. 鈥淓xposure 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.鈥� This has enabled epidemiologists to establish probabilities of exposure to one or more categories of products that may contain endocrine disruptors according to the mother鈥檚 occupation.
Endocrine disruptors associated with poorer sperm quality
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). 鈥淚n our study, the products most associated with these anomalies were pesticides, phthalates and heavy metals鈥�, notes Ronan Garlant茅zec.
鈥淭hese 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鈥�, Serge Nef continues. An additional study is already planned in this same population to study the link between maternal occupational exposure to endocrine disruptors and changes in sexual hormones during adulthood.
Preventing exposure to endocrine disruptors
The results of this study suggest an association between the mother鈥檚 occupational exposure to endocrine disruptors and a decrease in several semen parameters in their children during adulthood. 鈥淚t 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鈥檚 fertility鈥�, underlines Luc Multigner. 鈥淪imilarly, it would be interesting to carry out a similar study in women, in order to evaluate whether the impact of endocrine disruptors is the same on the female reproductive system, although this is much more complex to carry out鈥�, explains Ronan Garlant茅zec. Finally, the data concerns mothers 25 years ago. Since then, the professions exerted by women have greatly evolved, as has the presence of endocrine disruptors in the products used. 鈥淗ence the crucial preventive role of this study鈥�, concludes Serge Nef.