Abstract
The major function of the uterus is to accept and provide a suitable environment for an embryo, ultimately leading the birth of offspring and successful propagation of the species. For this occur, there must be precise coordination of hormonal signalling within both the endometrial and myometrial components of this organ. Non-coding RNAs, specifically, microRNAs (miRNAs) have been shown to be essential for normal uterine development and function. Within this organ, miRNAs are proposed to fine-tune the actions of the female steroid hormones estradiol and progesterone. Not surprising, mis-expression of miRNAs has been documented in diseases of the endometrium and myometrium such as endometriosis and leiomyomas, respectively. In this chapter, I will review the current understanding on the role, regulation and function of non-coding RNAs focusing on miRNAs in both the normal physiology of the endometrium and myometrium as well as in pathologies of these tissues, namely endometriosis and leiomyomas.