To compare the difference of the effect of CC or letrozole on follicle growth, evaluation event and hormonal profile (FSH, E2) in unexplained ifertility. Infertility clinic of FER sub-division of Obstetrics and Gynecology Division, Medical Faculty of Diponegoro University/Dr. Kariadi Central General Hospital, Semarang, Indonesia. Randomized double blind controled trial non matching. Randomized …