Impact of oral antibiotic treatment for chronic endometritis on pregnancy outcomes in the following frozen-thawed embryo transfer cycles of infertile women: a cohort study of 640 embryo transfer cycles.

OBJECTIVE:To investigate the therapeutic effect of antibiotic treatment on pregnancy outcomes in the following frozen-thawed embryo transfer cycles of infertile women. DESIGN:Retrospective study. SETTING:University assisted reproduction unit. PATIENT(S):A total of 640 women were included. Among them, the number of CD138+ cells per high-power field (CD138+/HPF) in the endometrium at the first evaluation was 0 in 88 women; 315 women had 1-4 CD138+/HPF and the remaining 237 had ≥5 CD138+/HPF. Finally, 26 of 237 women had persistent chronic endometritis (PCE) diagnosed. INTERVENTION(S):Hysteroscopy and endometrial biopsy were performed in the proliferative phase. After antibiotic treatment, endometrial biopsy samples were collected again. MAIN OUTCOME MEASURE(S):Live birth rate. RESULT(S):No significant difference in pregnancy outcomes was found between women with CD138+/HPF = 0 and those with CD138+/HPF 1-4. The cure rate was 89.0% in women with CD138+/HPF ≥5 after treatment. The implantation rate (51.6% vs. 32.3%, relative risk [RR] 2.23, 95% confidence interval [CI] 1.07-4.66), clinical pregnancy rate (65.7% vs. 42.3%, RR 2.62, 95% CI 1.17-5.86), live birth rate (52.1% vs. 30.7%, RR 2.45, 95% CI 1.04-5.76), and cumulative live birth rate (64.2% vs. 38.5%, RR 2.88, 95% CI 1.27-6.51) were all significantly higher in women with CD138+/HPF ≤4 than in women with PCE. CONCLUSION(S):CD138+/HPF ≤4 in the endometrium had no negative impact on pregnancy outcomes. Antibiotic treatment was an effective way to improve the reproductive outcomes of women with CD138+/HPF ≥5. PCE was associated with poorer pregnancy outcomes.