Novel endometrial receptivity test increases clinical pregnancy and live birth rates in patients with recurrent implantation failure: Secondary analysis of a prospective clinical trial

Abstract Objectives This study aimed to evaluate the efficiency of endometrial receptivity testing (ERT) in improving pregnancy outcomes for patients with recurrent implantation failure (RIF), and to investigate the incidence of implantation window displacement. Methods Conducted between April 2021 and August 2022, at a university‐affiliated reproductive center, the study included 85 RIF patients who had failed to achieve pregnancy after three embryo transfers. As part of a multicenter prospective cohort study (ChiCTR2200059342), 45 patients underwent ERT‐guided frozen single blastocyst transfer, while 40 received standard treatment without ERT. Endometrial preparation was performed using a hormone replacement therapy (HRT) protocol in the cycle preceding transfer. Endometrial sampling for ERT, including RNA sequencing, artificial intelligence, and discriminant analysis of endometrial receptivity, was conducted on day 5 after progesterone administration to determine the implantation window. The same HRT protocol was used in the transfer cycle, with embryo transfer timed according to the ERT‐calculated window. Results Our data showed that 28.07% of patients exhibited a displaced implantation window, all characterized by pre‐receptive endometrium. The ERT group had significantly higher clinical pregnancy rates (57.78% vs. 35.00%, p = 0.036) and live birth rates (53.33% vs. 30.00%, p = 0.030) compared with the non‐ERT group. Conclusion Our findings suggest that approximately one‐third of RIF occurrences may be due to endometrial factors, and ERT‐guided personalized embryo transfer significantly improves pregnancy outcomes, underscoring its value in reproductive medicine.