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.