The impact of the microbiome in the endometrial function: is it solely influenced by the local microbiome?

The human microbiome plays an important role in the physiology of many organs and alterations in its composition can be accompanied by serious pathologies. At the reproductive level, dysbiosis of the endometrial microbiota has been related to subfertility, recurrent implantation failures (RIF), and complications during pregnancy, such as preterm birth and spontaneous abortions. However, in recent years it has been observed that microbiome from other mucosal locations also influence women's fertility, ultimately affecting endometrial functionality. For example, the intercommunication and colonization capacity of microorganisms present in the vagina towards the uterine cavity is well documented, evidencing the influence of the vaginal microbiome on endometrial health. Additionally, the gut microbiome also plays a critical role in regulating the female reproductive endocrine system and has a significant impact on female reproductive health and associated conditions. This article aims to review recent findings on the influence of different microbiome locations on endometrial functionality.