Characterization Of The Vaginal Microbiota In Infertile Women With Repeated Implantation Failure

Objective Repeated implantation failure(RIF)refers to infertile patients under 40 years old who have undergone ≥ 3 transfer cycles and have accumulated at least 4 high-quality embryos and have failed to get pregnancy,which is a intractable problem in the field of assisted reproduction.However,little research has been carried out on the vaginal microbiota of infertile women with a history of repeated implantation failure.This study intends to compare the differences of vaginal microbiota between infertile women with a history of repeated implantation failure and those who achieved clinical pregnancy in the first frozen embryo transfer(FET)cycle,so as to explore the relationship between the species and abundance of vaginal microbiota in patients with repeated implantation failure,to lay a foundation for later research and treatment.Method From January 2019 to December 2020,infertile women in the Reproductive Center of the First Affiliated Hospital of Guangxi Medical University were selected as the research subjects.In this study,we characterized the vaginal microbiota of patients with a history of repeated implantation failure as RIF group(n=37),while those who achieved clinical pregnancy in the first FET cycle were used as controls(n=43).After DNA extraction and detection of the two groups of vaginal microbiota,the second-generation Illumina Hiseq whole-genome sequencing was performed to analyze the Alpha diversity and Beta diversity of the vaginal microbiota Genus and bacterial species differences,and microbial gene function annotation and identification of the differences between the two groups.Result Alpha diversity analysis on the relative abundance changes of vaginal microbiota in RIF group and control group showed that the Alpha-Shannon index diversity was higher in RIF group.There were certain differences in the beta diversity of microbiota between the two groups.The distribution of RIF group was relatively more discrete;The vaginal microbiota in the two groups were separated to some extent.At the phylum level,the relative abundances of Actinobacteria in RIF group was lower;At the bacterial family level,the relative abundances of Actinomycetaceae and Ruminococcaceae in RIF group were significantly higher than those in the control group.At the genus level,the relative abundances of Actinomyces and Subdoligranulum in RIF group were signficantly higher than those in the control group.At the species level,the relative abundances of Prevotella＿timonensis,Lactobacillus＿jensenii and Subdoligranulum＿unclassified species in RIF group were significantly higher than those in the control group.There were significant differences in GO function,among which the most significant difference was GO＿0071944 and four KEGG pathways,of which the significant differences in KEGG pathways were both signal transduction and cellular process-related isopotential pathways(K07288 and K08086).The genus Subdoligranulum had the strongest correlation with differential function at the genus level,and was significantly positively correlated with the four KEGG differential pathways and most differential GO.Conclusion Significant differences on phylum,family,genus,species,Alpha diversity and Beta diversity were presented in the vaginal microbiota between RIF group and control group.Among which Subdoligranulum genus had the strongest correlation with the difference.The mechanism of its association to repeated implantation failure remains to be further investigated.