Ling Zhang

China

Title: Exposure of women undergoing In-Vitro Fertilization to per-and polyfluoroalkyl substances: Evidence on negative effects on Fertilization and high-quality embryos

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Biography

    

Abstract

Abstract: The study to be shared at the conference explored the associations between in vitro fertilization (IVF) outcomes and plasma concentrations of individual PFAS and PFAS mixtures in women undergoing in vitro fertilization and embryo transfer (IVF-ET) and how these exposures might affect IVF outcomes.   

Background: Infertility is generally defined as the inability of a couple to develop pregnancy even after a year of unprotected frequent sexual intercourse. In April 2023, The World Health Organization (WHO) reported global data on infertility. The Western Pacific Region had the highest prevalence of lifetime infertility (23.2%), followed by the Region of the Americas (20.0%) and the European Region (16.5%). In countries like China, the rate of female infertility among reproductive age has increased to a reported prevalence of about 25%. There are several reasons for infertility, including advanced reproductive-age, unhealthy lifestyle, exposure to environmental toxins, and other issues. Endocrine disruptors (EDCs) have been considered as one of the factors leading to infertility, impairing female fertility by altering the hormonal environment that plays an important role in the pathogenesis of infertility.

Per-and polyfluorinated-alkyl substances (PFAS) are environmental endocrine-disrupting-chemicals (EDCs) and constitute a wide range of formulated compounds, characterized by carbon chains varying from 4 to 14 carbons in length adorned with multiple fluorine atoms. PFAS are recognized as problematic pollutants with adverse reproductive consequences, and these compounds have been widespread utilized in both market or commercial uses, including non-stick utensils foodstuffs, décor, carpets, cosmetics and along with different applications.

Objective: To investigate the joint effect of PFAS mixtures, a confounder-adjusted BKMR model analysis showed inverse relationship between PFAS mixtures and the number of high-quality embryos, 2PN zygotes and cleavage embryos, to which the greatest contributors to the mixture effect are PFDeA and PFBS, respectively. 

Methods: The study analyzed 8 PFASs in plasma samples from women (N=259) who underwent IVF treatment. In multivariable generalized linear mixed models, there were statistically significant associations of higher plasma concentrations of PFNA with reduced numbers of total retrieved oocytes [12.486 (95%CI:-0.446,25.418), p trend=0.017], 2PN zygotes [6.467(95%CI:-2.034,14.968), p trend=0.007], and cleavage embryos [6.039(95%CI:-2.162,14.240), p trend=0.008]. Similarly, there was a continuous decline in the numbers of retrieved 2PN zygotes and cleavage embryos with increasing concentration of PFOS [6.467(95%CI:-2.034,14.968), p trend=0.009 and 6.039(95%CI:-2.162,14.240), p trend=0.031,respectively] and a negative association between PFHxS concentrations and clinical pregnancy during the initial cycles of frozen ET [0.525(95%CI:0.410,0.640), p trend=0.021].

Results: The joint effect of PFAS mixtures, investigated through a confounder-adjusted BKMR model analysis showed inverse relationship between PFAS mixtures and the number of high-quality embryos, 2PN zygotes and cleavage embryos, to which the greatest contributors to the mixture effect are PFDeA and PFBS, respectively. It demonstrated that PFAS exposure might exert negative effects on oocyte yield, fertilization and high-quality embryo in women undergoing IVF. 

Conclusion: The findings of the study suggest that exposure to PFAS may increase the risk of female infertility and further studies are needed to uncover the potential mechanisms underlying the reproductive effects associated with PFAS.

SOURCE: Juan Shen, Yuchan Mao, Hongyan Zhang, Hangying Lou, Ling Zhang, Joaquim Paulo Moreira, Fan Jin, Exposure of women undergoing in-vitro fertilization to per-and polyfluoroalkyl substances: Evidence on negative effects on fertilization and high-quality embryos, Environmental Pollution, Volume 359, 2024, https://doi.org/10.1016/j.envpol.2024.124474.

(https://www.sciencedirect.com/science/article/pii/S0269749124011886)