The impact of endocrine disruptors on early pregnancy and clinical outcomes in IVF

Since more than 40 years, there are annual increasing of studies, meta-analysis reporting and discussing the potential associations between endocrine disrupting chemicals (EDCs) and human fertility potential declining. Today it’s accepted that a substantial number of environmental and exposition factors affect the fertility and fecundity capacity of couples during the peri and post conception period. It’s accepted that most of EDCs interfere with or mimic steroid hormone action; predominantly by affecting estrogen, androgen and thyroid hormones signaling pathways and disturbing specific molecular process on relation with single or multiple biological functions. Some of EDCs can interact with the male and female reproductive system and lead to endocrine disruption in the testis and ovary. they exert their effects mainly via binding transcription factor receptors, EDCs can alter endocrine function through a variety of mechanisms. At fertility age EDCs may alter the expression and/or activity of enzymes required for synthesis and/or catabolism of testicular and ovarian sex steroids and the expression of hormone receptors and/or their ability to bind their and endogenous ligands. For example, in male, the literature reported a negative correlation between disrupted spermatogenesis and lifestyle factors (environmental-professional expositions) such as alcohol consumption, cigarette smoking, drug use, and obesity caused by high-energy diet. In female infertility diseases, the negative impact of chemicals ED has been studied in animals. Many disorders have been described, such as low ovarian weight, impaired folliculogenesis, a high aneuploidy rate and the acceleration of follicular atresia. Indeed, women exposed to some endocrine-disrupting pesticides (such as atrazine, lindane) have an elevated risk of long menstrual cycles or anovulation but the most serious consequence is POF and endometriosis pathophysiology’s. In our IVF experience in Picardie region (France), we observed that various pesticides with an endocrine-disrupting action are associated with poor oocyte quality (maturation and competency), embryonic defects and poor IVF outcomes, and some pesticide compounds are linked to specific causes of female infertility, such as premature ovarian insufficiency, polycystic ovarian syndrome, and endometriosis. It was reported that EDCs can reduce embryo implantation chances and increase miscarriage, placenta and post-natal abnormalities. for endometrium receptivity and implantation failure EDCs can play by modifying keys elements of the immune response relevant to pregnancy, and disrupt immune tolerance required for robust placentation, optimal fetal development and be a as contributing risk factors in recurrent miscarriage, preeclampsia, preterm birth and related pathologic gestation Environmental insults, including endocrine disrupting chemicals during critical periods of fetal development, can alter DNA methylation patterns, leading to inappropriate developmental gene expression and disease risks. Similar to environmental factors, endocrine-disrupting chemicals can influence gene expression without modifying the DNA sequence. It is commonly accepted that the transgenerational inheritance of parentally acquired traits is conveyed by epigenetic alterations risks also known as “epimutations”. In Conclusion, the negative impact of exposure to various endocrine-disrupting is becoming now a worldwide public health. Indeed, the community should be informed about the fertility decline, low ongoing pregnancy rates, and elevated risk of miscarriage associated with exposure to high doses of pesticides for example. We must keep in mind that humans are exposed to EDCs mixtures composed of hundreds of chemicals every day and not a single chemical in isolation