Embryonic
miscarriage severely affects the life quality and physical and mental state of pregnant women. However, the detailed mechanism underlying embryonic
miscarriage is not fully understood. This study is aimed at analyzing embryonic
miscarriage. We collected samples from 25 normal pregnant women and 25 embryonic
miscarriage patients of similar age to analyze microbiota isolated from the vagina. Crude examination of the vagina isolates showed that compared with the control group, 80% of the embryonic
miscarriage group contained a significantly lower number of Lactobacillus, the major healthy microbe in the vagina. Furthermore, the levels of Th1 and Th2 secreted
cytokine interleukin 2 (IL-2) and interleukin10 (IL-10), respectively, were examined. Results showed that the
IL2 level was higher, and
IL10 level was lower in the embryonic
miscarriage group than in the control group, whereas the
IL2/
IL10 level was higher in the embryonic
miscarriage group than in the control group. This finding suggested that the immune response was suppressed in the embryonic
miscarriage group. To further dissect the microbiota of the vagina in the two groups, 16S
rDNA sequencing was performed. Bioinformatics analysis showed that 1096 and 998 overlapped operational taxonomic units were identified from the embryonic
miscarriage and control groups, respectively. At the genus level, the relative abundance of Fam_Finegoldia, Lac_Coprococcus_3, and Lac_Roseburia significantly differed in the embryonic
miscarriage group. Overall, our analyses provided potential
biomarkers for embryonic
miscarriage and elucidated the causative relationship between microbiota and immune responses and may enable the possible diagnosis and
therapeutics of
early pregnancy loss.