Abstract: Objective · To explore the uterine microbiota in women undergoing abortion and non-pregnant women. Methods · Fifty-six women who had experienced spontaneous abortion and 39 women who had experienced artificial abortion were selected to obtain the decidual tissuescurettage vacuum aspiration, and 10 non-pregnant women (without infection) were selected to obtain the endometrial tissues through gynecological surgery Department of Gynecology in Huadong Hospital. Three groups of samples were subjected to high-throughput sequencing based on the V4 variable region of the 16S ribosomal RNA (rRNA) gene, and the bacterial composition of each group of samples was analyzed. The diversity of uterine microbiota was compared among three groups. Results · Low-abundance microbiomes were detected the decidual tissues of abortion women and the endometrial tissues of non-pregnant women. Proteobacteria was the main phylum of the three groups, and Escherichia/Shigella was the main genus. The diversity of uterine microbiota in spontaneous abortion group was higher than that in artificial abortion group. Conclusion · There is a low-abundance uterine microbiota mainly composed of Proteobacteria. The dominant bacteria at the level of phylum, family and genus has no significant difference between the spontaneous abortion group and the artificial abortion group, but there is higher flora diversity in the spontaneous abortion group than in the artificial abortion group.

Key words: uterine microbiota, abortion, decidua, high-throughput sequencing, 16S rRNA gene