Alteration of vaginal microbiota in patients with recurrent miscarriage

The aim of this study was to characterise the structure of vaginal microbiota in unexplained recurrent miscarriage (RM). The vaginal bacterial communities of 16 patients with RM and 20 healthy volunteers were sampled. Then, the microbiomes of bacterial profiles of RM patients and healthy volunteers were compared by sequencing the V3-V4 regions of the bacterial 16S ribosomal RNA gene using the Illumina MiSeq platform (Illumina, San Diego, CA). Taxonomic analysis demonstrated that abundance of Lactobacillus and Gardnerella were significantly different between the RM and control groups. Furthermore, at the genus level, Lactobacillus was the most dominant genus in the two groups. Statistically significant differences were observed in three genera between RM and control groups. In the control group, two bacterial taxa were significantly more abundant (Lactobacillus and Gardnerella), while only one taxon was overrepresented in the RM group (Atopobium). These present findings provide experimental evidence supporting vaginal microbiota dysbiosis in women with RM.Impact statementWhat is already known on this subject? Currently, bacterial vaginosis is thought to be mainly due to the vaginal dysbacteriosis, which can induce unexplained recurrent miscarriage, premature rupture of membranes, low birth weight premature birth, premature birth, chorioamnionitis and series of diseases.What do the results of this study add? The current study demonstrated that Lactobacillus and Gardnerella were significantly decreased in RM patients compared to healthy control, while Atopobium was overrepresented in the RM group.What are the implications of these findings for clinical practice and/or further research? Clinically, women with RM might benefit from vaginal microbiota treatment, adjuvant therapy with Lactobacillus-based live biotherapeutics.