Ulipristal Versus Placebo for Women With Bleeding Induced by Mirena

The LNG-IUS is a contraceptive method with high efficacy, long acting, reversible with contraceptive failure between 0.1 and 0.5/100 women/year. It released 20 mcg/day of LNG with a life span duration of 5 years. LNG is a synthetic progestin, 19-northestosterone, six times more potent than progesterone, with androgenic properties and with binding with sexual hormones, receptors of human steroids, including receptors of glucocorticoids and mineralocorticoids, with minimal capacity of binding with estrogen receptors. At endometrium level it induce antiproliferative effect and strong expression of local markers and endometrial decidualization, including the prolactin receptor and insulin-like growth factor. The mechanism of action includes effect upon cervical mucus which affects the sperm movements through the reproductive tract which affects fertilization. In some women could be ovulation inhibition. One of the main reason for discontinuation is breakdown bleeding, increase bleeding or abnormal bleeding including heavy menstrual bleeding (HMB) and spotting which is common at the first six month of use. Despite the fact that it is the main cause of discontinuation, there is no effective treatment for these cases. An effective treatment could help in the reduction of reduce the rates of discontinuation, improved the cost-effectiveness and quality of life of users. A selective progesterone receptor modulator (SPRM) is Ulipristal Acetate (UPA) is approved in the European Union as Esmya® as a tretament to reduce the ueterine leiomyomas at te dose of 5 mg/day and it under evaluation at the dose of 5-10 mg as oral contraceptive. This could be an option of treatment for HMB or abnormal bleeding induced by the LNG-IUS. UPA is agonist/antagonist and binding with progesterone to the receptor level. It has ovarian and endometrial activity, with dose-dependent effect in inhibition of ovulation and maturation of the endometrium. There are restricted evidences, that the administration of UPA induce a quick endometrial atrophy and stop the abnormal bleeding.