P-319 Chronic endometritis prevalence, associated factors and pregnancy outcome among infertile women

Abstract Study question What are the prevalence, associated factors and pregnancy outcome of chronic endometritis(CE) among infertile women? Summary answer The overal prevalence of chronic endometritis in infertile women was 24.7%. Diagnosis rate of CE was higher in primary infertility compared to other infertility groups. What is known already Chronic endometritis is defined as a chronic inflammation of uterine endometrium. The prevalence of chronic endometritis varies across different groups and diagnostic criteria. The pathophysiology of chronic endometritis remained unclear, therefore, associated factors of chronic endometritis are uncertain. Study design, size, duration We perfomed an single-center, retrospective study between May 2019 and July 2023. By doing so, we collected data on 486 infertile women. Participants/materials, setting, methods A total of 486 infertile women, who underwent hysteroscopy by single surgeon, were recruited. The diagnosis of chronic endometritis was confirmed by presence of plasma cell per section in hematoxylin-eosin stain or CD138 immunohistochemical staining. Preoperative information (including age, body mass index, smoking, alcohol consumption, clinical presentation of infertility, endometrial thickness at ovulatory phase, anti-mullerian hormone (AMH) level and infertility factors) and post-operative information (including endometrial histology and pregnancy outcome) were collected. Main results and the role of chance The prevalence of chronic endometritis in the 486 infertile women with hysteroscopy guided endometrial biopsy was 24.7%. Prevalence of chronic endometritis was 28.1%, 19%, 22.2%, 27.2% in women with primary infertility, secondary infertility, recurrent pregnancy loss (RPL) and repeated implantation failure (RIF), respectively. A multivariate analysis revealed that overweight was associated with lower risk of chronic endometritis than underweight (relative risk (RR) = 0.56, 95% confidence interval (CI): 0.32-0.98, p = 0.042). Primary infertility was associated with higher risk of chronic endometritis than non-primary infertility (RR = 1.44, 95% CI: 1.02-2.03, p = 0.039). The pregnancy rate (including spontaneous pregnancies) was comparable between women with treated chronic endometritis and without chronic endometritis; 54.7% versus 61.7% in clinical pregnancy rate and 82.8% vs 85.4% in ongoing pregnancy rate. The prevalence of chronic endometritis with coexisting endometrial lesion (endometrial polyps, submucous myoma, or both of them) was 61.7%. Limitations, reasons for caution Our retrospective study has a less powerful design compared to a prospective randomized controlled study. Wider implications of the findings In women with primary infertility, the diagnosis rate of chronic endometritis was higher compared to other infertility groups. Therefore, even in cases of primary infertility, chronic endometritis should be considered as a potential cause of infertility. Trial registration number not applicable