The endometrial morphology , subendometrial blood flow index , the levels of serum estradiol ( E@ ) , progesterone ( P ) and luteinizing hormone ( LH ) on the day of injection of human chorionic gonadotropin ( hCG ) , the dosage and time of gonadotropin ( Gn ) , oocyte count , high-quality embryo number , embryo cultivation rate and clinical pregnant rate were observed in the two groups .