Lozano FM, Bernabeu A, Lledo B, et al. - Endometrial and vaginal microbiome of women with and without chronic endometritis were compared in this cohort study of 60 patients undergoing assisted reproductive technology treatment with their own or donated gametes. Researchers obtained vaginal and endometrial samples in the cycle prior to embryo transfer. In patients with endometritis, vaginal samples exhibited a higher alpha-diversity index and endometrial samples showed significant differences. The groups did not show significant differences in the beta-diversity analysis. Microbiome pattern, not dominated by Lactobacillus spp., was identified in vaginal and endometrial samples from women with endometritis. In relative abundance analysis, endometrial samples had Ralstonia and Gardnerella spp., and vaginal samples had Streptoccoccus and Ureaplasma spp. in patients diagnosed with endometritis on CD138 immunohistochemistry. Performing comparison of endometrial and vaginal samples diagnosed with endometritis on CD138 immunohistochemistry, significant differences were observed in both alpha diversity and beta diversity. These sample groups had presence of Lactobacillus spp., Ralstonia spp., Delftia spp. and Anaerobacillus spp. As per these results, a characteristic vaginal and endometrial microbiota exists in patients with endometritis. A clear relationship was evident between changes in the vaginal microbiome and endometritis.