Objective: To compare pregnancy rates resulting from oral Dydrogesterone with vaginal progesterone for luteal phase support in in vitro fertilization. Design: A randomized multicenter clinical trial. Setting and conduct and participants including major eligibility criteria: This study is done in infertility clinic of Taleghani and Mahdieh Hospital, martyr Beheshti University, Tehran, Iran from April 2014 until January 2015, 200 infertile patients that are in age range of 20 -45 years old and don’t have any anomaly in uterine cavity evaluation and don’t have any advanced endometriosis, dense pelvic adhesion,genital TB, previous intracytoplasmic sperm injection failures which thay are undergoing intra cytoplasmic sperm injection-Embryo transfer cycles are including in this study. Interventions: patients randomly have been divided into two groups or 40mg dydrogesterone (Tablet duphaston 10mg, The pharmaceutical company Abbot,Netherland) ) or vaginal suppositories progesterone (suppository, 400mg , Actoverco , Great Britain) that started on oocytes recoverys day and This medication will be continued until 12 weeks of pregnancy. Main outcome measures: Clinical pregnancy rate. second outcomes measures: chemical and ongoing pregnancy and miscarriage rates, patient acceptance