PGR and leiomyoma: Progesterone completes the development and proliferation of leiomyomas (Kim et al., 2009; Ishikawa et al., 2010; Reis et al., 2016), and estradiol increases the availability of progesterone receptors on the cells and allows for more sensitivity to progesterone, thus increasing development (Ishikawa et al., 2010; Kim et al., 2013; Reis et al., 2016).