Effect of cell-free mitochondrial DNA mutations in follicular fluid on oocyte maturation and clinical pregnancy rates in women undergoing in vitro fertilization.

Abstract

[eng] Background: In vitro fertilization (IVF) outcomes are influenced by various factors, including the quality of the oocyte which may be impacted by genetic and environmental conditions. Recent advancements in reproductive medicine have highlighted follicular fluid analysis as a non-invasive method to identify biomarkers predictive of embryo implantation potential and overall IVF success. Among these, cell-free mitochondrial DNA (cf-mtDNA) has emerged as a promising candidate, with its mutations potentially indicating oocyte quality and embryo viability. Objective: Our aim is to explore the impact of IVF ovarian stimulation treatment on the accumulation of mitochondrial DNA (mtDNA) mutations in follicular fluid and assess their implications on IVF outcomes. Methods: This study enrolled 24 women under 35 years old undergoing their first IVF cycle without known infertility issues. For each woman, we collected a blood sample prior to ovarian stimulation and a follicular fluid sample at the time of oocyte retrieval. Long-PCR amplification and next-generation sequencing were used to identify mtDNA mutations. Embryo quality was assessed using the ASEBIR scoring system. Results: The ovarian stimulation step was associated with the induction of mtDNA mutations, reflected on the cf-mtDNA within follicular fluid, predominantly in the D-loop region. These mutations correlated with a lower oocyte count and poorer embryo quality, negatively impacting IVF outcomes. The accumulation of these mutations showed a timedependent pattern, with longer treatments leading to more mutations and lower pregnancy rates, likely due to increased oxidative stress and its deleterious effects on oocyte quality. Conclusions: The study establishes a link between mtDNA mutations in follicular fluid and reduced IVF efficacy, suggesting that such mutations could serve as non-invasive biomarkers for predicting IVF outcomes. This research paves the way for future investigations in the field of IVF with the aim of improving protocols by shortening the duration of ovarian stimulation or using antioxidants to reduce the mtDNA mutation rates. Altogether, it will lead to improved IVF outcomes and ultimately benefiting our patients