Abstract
PURPOSE: This study aimed to evaluate the pregnancy outcomes of frozen embryo transfer (FET) in patients with persistent chronic endometritis (PCE). METHODS: 186 patients were stratified into three groups: Cured CE (CCE), Cured Persistent CE (CPCE), and Still Persistent CE (SPCE). Only the first post-treatment FET cycle per patient was analyzed. RESULTS: Among women aged 20-48, the biopsy-based prevalence of CE and PCE was 14.23% and 1.30%, respectively. The SPCE group underwent more antibiotic treatments and endometrial pathology examinations, with a higher proportion of GnRH-a + HRT cycles compared to the CCE and CPCE groups. Clinical pregnancy rates were 41.67%, 37.21%, and 52.17%, while live birth rates were 31.67%, 30.23%, and 43.48% for the CCE, CPCE, and SPCE groups, respectively. No statistically significant differences were observed among the groups. Multivariate analysis confirmed that AMH (aOR 1.135; 95% CI 1.005-1.282) and pre-transfer endometrial thickness (aOR 1.259; 95% CI 1.07-1.49) are significantly associated with clinical pregnancy. CONCLUSION: Our exploratory findings suggest that PCE may not necessarily impair FET outcomes under individualized management. Ovarian reserve and endometrial thickness appeared to be more robust predictors of success than histologic persistence in this cohort. Due to the small PCE sample size, these results are hypothesis-generating and warrant validation in larger prospective trials. TRIAL REGISTRATION: This study is registered with China Medical Research Online (Registration Number: MR-44-24-022293, www.medicalresearch.org.cn).