Endometrial polyp is associated with a higher prevalence of chronic endometritis in infertile women

To assess the prevalence of chronic endometritis (CE) among infertile women with endometrial polyps (EP).From June 2017 to October 2021, 583 patients in the polyp group (group A-group A1: single-polyp group, 322 patients; group A2: multiple-polyp group, 261 patients) and 4534 patients in the non-polyp group (group B) were included in this retrospective study. Hysteroscopic polypectomy was performed in group A. Endometrial biopsy and CD138 immunohistochemistry staining for specimens was carried out in all groups.Prevalence of CE was significantly higher in group A than in group B (45.28% vs. 27.94%, P < 0.001). A significantly higher prevalence of CE was found in group A1 and group A2 compared with group B (42.24% vs. 27.94%, P < 0.001; 49.04% vs. 27.94%, P < 0.001; respectively). No significant difference in the comparison of CE prevalence was found between group A1 and group A2. Similar results were achieved in the subgroup analysis among patients aged 40 years or older and patients younger than 40 years.EP, either single EP or multiple EP, positively correlates with CE. The prevalence of CE was similar between the single-polyp group and the multiple-polyp group.