Reproductive History and Clinical Symptom-Related Risk Factors for Chronic Endometritis in Infertile Women: A Retrospective Case-Control Study

<b>Aims/Background</b> The diagnosis of chronic endometritis (CE) in infertile women without demonstrable intrauterine abnormalities remains a significant clinical challenge. The primary aim of this study was to identify the independent risk factors for CE regarding reproductive history and clinical symptoms in infertile women, providing evidence-based guidance for targeted CE screening in this population. <b>Methods</b> In this retrospective case-control study, a total of 180 infertile female patients undergoing hysteroscopy between October 2022 and July 2024, who fulfilled the enrollment criteria, were included. The participants were divided into two groups: non-chronic endometritis (NCE) group (<i>n</i> = 78) and CE group (<i>n</i> = 102). CE was diagnosed based on the syndecan-1 (CD138) immunohistochemical staining results. To evaluate the association of CE with reproductive history and clinical symptoms, both univariate and multivariate logistic regression analyses were conducted. <b>Results</b> The prevalence of CE in this study was 56.67% (102/180). Univariate logistic regression analysis revealed statistically significant differences in gravidity, parity, abortion history, and prolonged menstruation between the two groups (<i>p</i> < 0.05), indicating their correlations with CE. Further multivariate analysis identified abortion history (odds ratio [OR] = 2.521, 95% confidence interval [CI]: 1.307-4.864, <i>p</i> = 0.006) and prolonged menstruation (OR = 3.624, 95% CI: 1.141-11.513, <i>p</i> = 0.029) as independent risk factors for CE, while gravidity and parity showed no significant associations after adjustment. <b>Conclusion</b> Abortion history and prolonged menstruation are independent risk factors for CE. For infertile women presenting with a history of abortion or prolonged menstruation but without apparent intrauterine abnormalities, hysteroscopy combined with CD138 immunohistochemical staining is recommended to facilitate early diagnosis and prompt therapeutic intervention for CE.