Assessment of the implantation window and embryonic factor impact to the treatment of recurrent implantation failure (RIF). A prospective study

Abstract

The aim: to study of the prognostic value of endometrial receptivity and preimplantation genetic diagnosis of embryos, and their influence on the effectiveness of in vitro fertilization (IVF) programs. We also evaluate the importance of this factor in comparison with other potential causes of infertility. Materials and methods: This prospective cohort study included 123 infertile women who underwent in vitro fertilization (IVF) treatment. 93 patients had repeated unsuccessful implantation attempts and were divided into three groups: group 1 - patients who were treated using genetically untested embryos according to a standard fixed stimulation protocol, group 2 - patients who were treated using euploid embryos after preimplantation genetic screening according to standard fixed protocol; group 3 - patients who underwent treatment using euploid embryos after pre-implantation genetic screening and determination of the implantation window with subsequent modification of the stimulation protocol, according to the endometrial examination result. 30 patients had a first attempt at IVF, which was carried out using genetically untested embryos, according to a standard fixed protocol, and made up the control group (CG). Determination of the window of implantation was carried out by triple aspiration biopsy of the endometrium during the luteal phase of the menstrual cycle since the endometrium is most susceptible to implantation during this period. Samples were analyzed using scanning electron microscopy. Based on the results obtained, the endometrial preparation protocol was individualized for the next attempt. preimplantation genetic testing (PGT) of embryos was carried out by the next generation (NGS) method. Statistical analysis was performed using IBM SPSS V25.0 for Windows software. Results: According to the obtained results, patient characteristics, screening rates, IVF cycle characteristics, and the number, quality, and stage of transferred embryos were compared between groups. The rate of clinical pregnancy was 46.7 % among patients of group 1.70 % among patients of group 2, 82.8 % among patients of group 3 and 50.0 % of the control group and statistically significantly different between groups (χ2=10.955, p= 0.012). The rate of live birth was 43.3 % among patients of group 1, 53.3 % among patients of group 2, 72.4 % among patients of group 3 and 43.3 % - of the control group, however, it did not differ statistically significantly between groups (χ2=6,639, р=0,084) Conclusions: The unique window of implantation and the embryonic factor are among the main reasons for multiple failed implantation attempts. Personalization of the endometrial preparation protocol and preimplantation embryo diagnosis are effective methods to improve IVF outcomes