{"paper_id":"b7a8682b-a5b8-4916-b936-c18eb634c998","body_text":"Abstract\nBoth chronic endometritis and endometriosis are common entities in infertile patients. The association and the co-existence of these two entities are poorly evaluated. The aim of this systematic review and meta-analysis was to examine the association between chronic endometritis and endometriosis and to find the prevalence of chronic endometritis in women with endometriosis. A systematic electronic search was conducted using the MEDLINE, Scopus and Cochrane databases up to May 2022. Observational studies which examined the prevalence of chronic endometritis in women with endometriosis were included. Newcastle–Ottawa Scale was used for the quality assessment. Odds ratios (OR) with 95% confidence intervals (CIs) for dichotomous outcomes and pooled prevalences with 95% CIs were calculated. 855 studies were identified, of which six studies were included in the systematic review and five in the meta-analysis. The prevalence of chronic endometritis in women with endometriosis was 28%, with higher frequency observed in women with endometriosis rASRM stage III-IV (43%) in comparison to women with endometriosis rASRM stage I-II (25%). The meta-analysis showed a significantly higher chronic endometritis in women with endometriosis in comparison to the control group (five studies, 264 endometriosis vs. 435 control, OR = 2.07; 95% CI 1.11–3.84, I2 43%, p = 0.02). The present meta-analysis showed a significantly higher risk of chronic endometritis in women with endometriosis in comparison to the control group. 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Reprod Biomed Online. 2021;42(5):939–51.\nDarici E, Blockeel C, Mackens S. Should we stop screening for chronic endometritis? Reprod Biomed Online. 2023;46(1):3–5.\nFunding\nThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\nAuthor information\nAuthors and Affiliations\nContributions\nDRK and NS were involved in the conception and design of the study. UC, PD and GS were involved in the acquisition of data, analysis and interpretation of data, and drafting of the article. BL, AKS, DRK, NS, PD and UC were involved in revising the manuscript critically for important intellectual content. DRK was responsible for final approval of the version to be submitted.\nCorresponding author\nEthics declarations\nEthics Approval\nNot applicable.\nConsent to Participate\nNot applicable.\nConsent for Publication\nNot applicable.\nConflicts of Interest\nDRK has nothing to disclose related to this study, UC has nothing to disclose related to this study, AKS has nothing to disclose related to this study, GS has nothing to disclose related to this study, BL has nothing to disclose related to this study, PD has nothing to disclose related to this study, NS has nothing to disclose related to this study.\nAdditional information\nPublisher's Note\nSpringer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.\nRights and permissions\nSpringer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.\nAbout this article\nCite this article\nKalaitzopoulos, D.R., Catena, U., Schwartz, A.K. et al. Chronic Endometritis and Endometriosis: Two Sides of the Same Coin?. Reprod. Sci. 32, 474–487 (2025). https://doi.org/10.1007/s43032-025-01785-y\nReceived:\nAccepted:\nPublished:\nVersion of record:\nIssue date:\nDOI: https://doi.org/10.1007/s43032-025-01785-y","source_license":"CC0","license_restricted":false}