Increasing the efficiency of assisted reproductive technology programs based on the identification and correction of endometrial risk factors in patients with recurrent implantation failure

BACKGROUND: Recurrent implantation failure remains a key reason for the ineffectiveness of assisted reproductive technology programs. It has been shown that a significant proportion of patients with recurrent implantation failure have impaired endometrial receptivity and uterine microflora dysbiosis, which necessitates an in-depth examination of the endometrial factor as a possible cause of unsatisfactory assisted reproductive technology outcomes. AIM: The aim of this study was to increase the effectiveness of thawed embryo transfer programs by correcting the uterine microflora and individualizing the implantation window in patients with recurrent implantation failure. METHODS: This prospective, controlled, non-randomized, open-label study included patients with recurrent implantation failure who underwent thawed embryo transfer programs. In the main group, Endometrial Receptivity Analysis (Igenomix, Spain) and Endometrial Microbiome Metagenomic Analysis (Igenomix, Spain) tests were performed, followed by adjustment for transfer timing and endometrial microbial composition. The implantation rate, clinical pregnancy rate and live birth rate were compared between the main and comparison groups, the univariate correlation analysis of risk factors being performed. RESULTS: Of 107 patients in the main group, implantation window displacement was detected in 51.85%, a decrease in the proportion of Lactobacillus spp. in 74.08%, and dysbiosis in 14.81%. The implantation rate, clinical pregnancy rate and live birth rate were higher in the main group either with or without preimplantation genetic testing (p 0.05). An association was established between the presence of intrauterine interventions and the development of dysbiosis (p = 0.0053), as well as between chronic endometritis and decreased receptivity (p = 0.006). CONCLUSION: A comprehensive assessment of the microflora and endometrial receptivity with subsequent personalized correction can increase the effectiveness of assisted reproductive technology programs in patients with recurrent implantation failure. The use of molecular genetic tests can be recommended as an important stage of clinical examination in patients with recurrent implantation failure before repeated embryo transfer.