P–518 Assessment of mitochondrial DNA viability ratio in day–4 biopsied embryos as an add-in to select euploid embryos for single embryo transfer

Abstract

Study question Is mitochondrial DNA viability ratio of day–4 biopsied embryos associated with embryo implantation potential? Summary answer The mitochondrial DNA viability ratio is significantly higher in embryos that implant. The score might help to select euploid embryos for single embryo transfer. What is known already Embryo euploidy is a critical factor for successful pregnancy outcomes. However, transfer of euploid embryos does not invariably result in implantation, thus indicating that other factors may play a role. Metabolic rates and adenosine triphosphate content vary significantly in oocytes and embryos and might affect embryo viability. Embryo function, indirectly measured by mitochondrial DNA viability ratio (mtV) has emerged as a potential quantitative biomarker for embryonic selection before the transfer, but clinical data remains limited. The purpose of this study is to characterize and compare mtV in euploidy day 4 embryos. Study design, size, duration Retrospective cohort study carried out between Jan. 2017 to Jan. 2020, involving 75 infertile couples undergoing IVF-ICSI with PGT-A and single embryo transfer (SET) of day 4 euploid embryos. Participants/materials, setting, methods We compared the mtV ratios of 34 non-pregnant patients with those of 41 patients who achieved clinical pregnancy after SET. The mtV ratio was obtained from a cohort of 75 euploidy embryos. The embryos were biopsied 80–85 hours post–ICSI and subjected to next-generation sequencing (NGS). The mtV was determined using Multiple of Mean (MoM) values, obtained by dividing the mtV ratio of individual embryos by the mean mtV value of all implanted embryos. Main results and the role of chance The mean mtV ratio (1.51; 95% confidence interval [CI] 1.25–1.77) of non-pregnant patients was significantly lower than those of pregnancy counterparts (2.5; 95% CI 1.82–2.68; p < 0.01). At a 0.5 MoM cutoff, the sensitivity and specificity of mtV ratio to discriminate between implanted embryos versus non-implanted embryos were 35.3% and 78.2%, respectively., with a positive predictive value (PPV) of 41.4%. Limitations, reasons for caution Our study is limited by the small sample size and lack of stratification by causes of female/male infertility. Endometrial receptivity issues, which could have contributed to implantation failure, was not evaluated. Wider implications of the findings: Assessment of mtV ratio could provide additional prognostic information for selecting euploid embryos for transfer in SET programs. Further research is warranted to establish the clinical utility of routine application of mtV evaluation in PGT programs. Trial registration number N/A