Second group: Patient with stair step protocol Follicular development will be monitored using transvaginal ultrasound at 11-14 day after (50mg) clomiphene for 5 days if there is no response (no follicle >10mm), so, (100mg) clomiphene will be initiated immediately for 5 days and ultrasound will be repeated 1 week after the first ultrasound. If there is no response, (150mg) clomiphene will be initiated immediately for another 5 days and TV/US will be performed 1 week after the second TV/US .