GNRH1 and Ovarian cyst: In recent Cochrane review it was stated, that combined OCP pre-treatment in GnRH antagonist cycles is associated with fewer clinical pregnancies and more days and a higher amount of gonadotrophin therapy and progestogen pre-treatment in GnRH agonist cycles, is associated with more clinical pregnancies and fewer ovarian cysts, at last, in estrogen pre-treated GnRH antagonist cycles, compared to no pre-treatment, more oocytes are retrieved but a higher amount of gonadotrophin therapy is needed (13).