Endometrial congestion is the only hysteroscopic finding indicative of chronic endometritis.

Chronic endometritis (CE), an inflammatory condition characterized by plasma cell infiltration within the endometrial stroma, is prevalent among women experiencing unexplained infertility or recurrent miscarriages. CE is traditionally diagnosed by endometrial biopsy using CD138 immunohistochemistry staining. Despite some studies suggesting hysteroscopy as an alternative diagnostic tool, its reliability compared with biopsy remains controversial. This study evaluated the diagnostic accuracy of hysteroscopy for CE by examining endometrial features, such as congestion, micropolyps, edema, and polyps, and comparing these with biopsy-confirmed cases of CE. This retrospective observational study was conducted at Toho University Omori Medical Center between June 2017 and November 2019 and included patients undergoing both hysteroscopy and histopathological examination. Endometrial congestion was identified as the only hysteroscopic finding significantly associated with CE, showing a moderate diagnostic agreement with biopsy results. These findings highlight the importance of further investigating hysteroscopic features of CE and their diagnostic implications and identify endometrial congestion as a potential predictive marker for CE.