Higher Prevalence of Chronic Endometritis in Women with Cesarean Scar Defect: A Retrospective Study Using Propensity Score Matching.

(1) Background: A cesarean scar defect may cause localized inflammation of the endometrial tissue, and various researchers believe that the presence of a cesarean scar defect is associated with chronic endometritis. However, there is no report on the possible association between cesarean scar defects and chronic endometritis thus far. This study aimed to assess the role of having a cesarean scar defect in a person's susceptibility to chronic endometritis. (2) Methods: This retrospective propensity-score-matched study comprised 1411 patients with chronic endometritis that were admitted to Henan Provincial People's Hospital in China from 2020 to 2022. Based on whether a cesarean scar defect was present or not, all cases were assigned to the cesarean scar defect group or the control group. (3) Results: Of the 1411 patients, 331 patients with a cesarean scar defect were matched to 170 controls. All unbalanced covariates between groups were balanced after matching. Before matching, the prevalence of chronic endometritis in the cesarean scar defect group and in the control group was 28.8% and 19.6%, respectively. After correcting for all confounding factors, a logistic regression analysis showed that cesarean scar defect occurrence may increase the risk of chronic endometritis (odds ratio (OR), 1.766; 95% confidence interval (CI), 1.217-2.563; = 0.003). After matching, the prevalence of chronic endometritis was 28.8% in the cesarean scar defect group and 20.5% in the control group. Thus, even after correcting for all confounding factors, the logistic regression analysis still showed that a cesarean scar defect remained an independent risk factor for chronic endometritis prevalence (OR, 1.571; 95% CI, 1.021-2.418; = 0.040). The findings were consistent throughout the sensitivity analyses. (4) Conclusions: The present results suggest that the onset of a cesarean scar defect may increase the risk of chronic endometritis.