Chronic endometritis and recurrent implantation failure: prevalence, diagnostic approaches and therapeutic strategies - a systematic review.

This systematic review (PROSPERO CRD420251151402) examined the relationship between chronic endometritis and recurrent implantation failure, focusing on prevalence, diagnostic strategies, and treatment-related reproductive outcomes. A comprehensive search of MEDLINE, Embase, Global Health, Cochrane Library, Web of Science, Health Technology Assessment Database, and ClinicalTrials.gov was performed. In total, 24 eligible studies were identified that exclusively included women with recurrent implantation failure evaluated for chronic endometritis using CD138 plasma cell immunohistochemistry and/or hysteroscopy. Due to substantial heterogeneity in diagnostic criteria and outcome reporting, the findings were synthesized narratively. The reported prevalence varied widely between studies (7.7-63.8%), and largely reflected differences in the CD138 plasma cell threshold applied. Antibiotic therapy achieved histological resolution in most cases; however, it remains uncertain whether this translates into higher clinical pregnancy or live birth rates compared with control populations, as the available studies reported mixed and inconsistent findings. The evidence regarding combined therapeutic strategies was similarly limited and heterogeneous, precluding firm conclusions regarding their effectiveness. Overall, the certainty of evidence was low. Standardized diagnostic criteria and adequately powered prospective studies are required to clarify the clinical relevance of screening and treatment for chronic endometritis in this population.