P-485 Performance of ERA test after PGT-A in RIF patients defined according to ESHRE 2023 good practice recommendations: a retrospective case-control study

Abstract Study question Is Endometrial-Receptivity-Array (ERA) test clinically-useful among Repeated-Implantation-Failure (RIF) women defined according to ESHRE 2023 good-practice-recommendations (GPR) and undergoing single euploid blastocyst transfer? Summary answer ERA-test showed a higher “non-receptive endometrium” rate among RIF. Nevertheless, the live-birth-rate (LBR) per first euploid transfer was independent from progesterone timing according to ERA-test. What is known already ERA-test evaluates the expression of 238 genes from an endometrial biopsy. It aims at predicting the window of implantation and adjust progesterone timing accordingly. The data are controversial due to poor study design and/or limited sample size. Few studies investigated ERA-test in a setting with euploid transfers and/or among RIF patients. Moreover, RIF definition is largely inconsistent leading to a significant bias in the interpretation of the existing literature and treatment. ESHRE 2023 GPR revised RIF definition. Here, we leveraged this updated definition and PGT-A to assess ERA-test diagnostic/therapeutic performance in these women. Study design, size, duration Retrospective case-control study during 2013-2021 including 2211 patients with at least one euploid blastocyst after PGT-A. Hysteroscopy was conducted in case of suspect uterine pathologies, biopsy in case of suspect inflammation, and therapy in case of endometritis. 265 patients (12%) were classified RIF according to the ESHRE GPR (= no successful implantation despite an estimated cumulative chance ≥60%). 48 RIF patients requested ERA-test before undergoing vitrified-warmed euploid single blastocyst transfer, while 217 did not. Participants/materials, setting, methods qPCR/NGS-based PGT-A was conducted to assess non-mosaic aneuploidies. Normal thyroid function, vitamin-D levels, uterine cavity, and absence of sactosalpynx were confirmed. Whenever the ERA test suggested altered receptivity, progesterone timing was modified accordingly. The primary outcome was LBR per first euploid transfer in the non-ERA versus ERA groups, with a sub-analysis in ERA receptive versus non-receptive. Outcomes were adjusted for confounders assessed via logistic regressions. Main results and the role of chance RIF patients requesting ERA-test were older (39.1±4.5 versus 36.7±3.5 years, p