Abstract:

At present, many studies show that the microbiome of female genital tract plays a vital role in maintaining normal pregnancy and influencing reproductive outcomes. Normal intrauterine flora (intrauterine symbiotic flora) can maintain the homeostasis of intrauterine environment and provide good conditions for embryo implantation. However, the mechanism of its interaction with the host during embryo implantation is still poorly understood. When the intrauterine symbiotic flora is disordered, it may change the intrauterine microenvironment by destroying the antibacterial barrier, causing immune cell imbalance, promoting the release of inflammatory factors and producing abnormal metabolites, so as to reduce the endometrial receptivity and lead to embryo implantation failure. Therefore, it is of great significance to study the interaction between host and microbiome and the influence of abnormal intrauterine flora on the physiology and function of local endometrial microenvironment. In this article, we summarized the composition of normal intrauterine symbiotic flora, the characteristics of intrauterine flora in infertile patients and the interaction mechanism between intrauterine flora and host during embryo implantation periods, in order to provide new ideas for further studies about intrauterine flora in embryo implantation in the future.

Key words: Uterus, Microbiota, Embryo implantation, Infertility, female, Pregnancy outcome