Abstract:

Chronic endometritis (CE) is an inflammatory disease characterized by endometrial stromal edema, hyperemia, irregular thickening, and the presence of plasma cell infiltration. Recent studies have demonstrated that CE can reduce endometrial receptivity through multiple mechanisms, leading to adverse pregnancy outcomes such as infertility, recurrent implantation failure, and recurrent miscarriage. The specific mechanisms include: the disorder of the intrauterine immune microenvironment caused by the imbalance of the proportions of endometrial immune cells; the disruption of the intrauterine microbial homeostasis due to the decrease in the abundance of Lactobacillus and the increase of conditional pathogens; the dysregulation of the hormonal regulatory network resulting from the increased expression of estrogen receptors and the decreased responsiveness to progesterone; and the abnormal angiogenesis of the endometrium triggered by the overexpression of pro-angiogenic factors such as hypoxia-inducible factor and vascular endothelial growth factor. Elucidating the relationships between the above mentioned mechanisms and endometrial receptivity could provide a theoretical basis for the accurate clinical diagnosis, targeted therapies of CE, and the improvement of reproductive outcomes, and is of great significance for safeguarding female reproductive health.

Key words: Endometritis, Pregnancy outcome, Embryo implantation, Chronic endometritis, Endometrial receptivity