Endocrine disruption and reproduction
Endocrine disruption
Studies from the scientific literature indicate that glyphosate has the capacity to interfere with the normal function of hormones in different animal species, including humans, and therefore may cause what is known as “endocrine disruption”. Exposure to chemicals that are endocrine disruptors or EDCs (or Endocrine Disrupting Chemicals) has been linked to a wide range of endocrine-related diseases related to growth, metabolism, cognition and reproduction, among others. A recent review highlights that out of the 10 common functional properties of endocrine disruptors, glyphosate fulfils at least eight of them. For example, glyphosate alone and glyphosate-based products have been shown to alter the hormone metabolism in different mammalian cell lines (Thongprakaisang et al., 2013; Walsh et al., 2000). Other studies have reported interactions with the hormones of reproduction, such as reducing the conversion of androgens to oestrogens (resulting in the production of more male than female hormones), with formulations causing a stronger effect (Defarge et al., 2016; Richard et al., 2005), and inducing oestrogenic responses without activating directly the oestrogen receptor (Mesnage et al., 2017) or via non-genomic mechanisms involved in cell proliferation (Sritana et al, 2018). In experimental studies with mice, glyphosate-based products have been shown to alter the reproductive hormone metabolism and reduce fertility (Varayoud et al., 2017 ; Romano et al., 2012; Romano et al., 2010).
Reproduction
Public scientific literature indicates that glyphosate may cause adverse effects on male and female reproduction and evidence suggests that these are caused via endocrine-related mechanisms. In humans, there is worrying evidence suggesting that glyphosate exposure can have negative effects during pregnancy. Maternal glyphosate and AMPA levels have been linked to a shortened gestational length in women with spontaneous deliveries (Lesseur et al. 2022), and female infants were born with higher anogenital distance, a typical indicator of endocrine disruption (Lesseur et al. 2021). Exposure to glyphosate has also been linked to an increased risk of late abortions in women (Arbuckle et al. 2001). On the other hand, in men, incubation of human semen with glyphosate appears to reduce sperm quality and motility (Anifandis et al. 2018).
More evidence is available from animal experiments. For example, it’s been reported that exposure to glyphosate may result in altered hormone levels and embryo losses in female pregnant rats, reduced offspring weight, as well as induced endometrial diseases and malformations in the ovarian tissues (Lorenz et al 2020, Ren et al 2018). Maternal exposure to glyphosate altered testis morphology and testosterone levels in male pups and resulted in lower sperm quality and production when they reached puberty (Pham et al. 2019), Similarly maternal and early life exposure of male pups resulted in decreased available testosterone levels and an increase of anogenital distance, a characteristic of endocrine-disrupting chemicals (Manservisi et al. 2019).
Resources
Articles :
Génération Futures (2022) : a scientific synthesis of the INRAe, mechanisms of action of glyphosate and glyphosate-based herbicides on male and female fertility in model animals and humans
HEAL (2019) : The exposure to glyphosate-based herbicides has been linked to endocrine and developmental effects by a new scientific pilot study
US Right to know (2020) by Carey Gillam : New research adds evidence that weed killer glyphosate disrupts hormones
US Right to know (2020), by Carey Gillam : New weed killer studies raise concern for reproductive health
Scientific research papers:
Arbuckle TE et al., “An exploratory analysis of the effect of pesticide exposure on the risk of spontaneous abortion in an Ontario farm population”, (Environ Health Perspect. 2001).
Anifandis, G. et al., “The Effect of Glyphosate on Human Sperm Motility and Sperm DNA Fragmentation”, (Int. J. Environ. Res. Public Health 2018).
Thu Ha Pham at al., “Perinatal Exposure to Glyphosate and a Glyphosate-Based Herbicide Affect Spermatogenesis in Mice”, (Toxicological Sciences 169(1), 2019).
Manservisi, F., et al., “The Ramazzini Institute 13-week pilot study glyphosate-based herbicides administered at human-equivalent dose to Sprague Dawley rats: effects on development and endocrine system”, (Environ Health 18, 15, 2019).
Lorenz V, et al., “Perinatal exposure to glyphosate or a glyphosate-based formulation disrupts hormonal and uterine milieu during the receptive state in rats”, (Food Chem Toxicol. 2020).
Lesseur C et al., “Maternal urinary levels of glyphosate during pregnancy and anogenital distance in newborns in a US multicenter pregnancy cohort” (Environ Pollut. 2021).
Muñoz JP et al., “Glyphosate and the key characteristics of an endocrine disruptor: A review”, (Chemosphere. 2021).
Gerona, R.R. et al., “Glyphosate exposure in early pregnancy and reduced fetal growth: a prospective observational study of high-risk pregnancies”, (Environ Health 21, 95 (2022)).
Lesseur C et al., “Urinary glyphosate concentration in pregnant women in relation to length of gestation” (Environ Res. 2022).