IRCT20120104008611N14 IRCT 2023-07-19 Tehran University of Medical Sciences the effect of letrozole on endometrial thickness Investigating the effect of letrozole on endometrial thickness in IVF candidate patients at Yas Hospital infertility clinic 2023-07-23 anticipated 100 Complete https://irct.ir/trial/70945 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Randomization description: Random allocation rule: First, 50 letters A and 50 letters B are written on special papers that are not marked inside. Then all of them are placed in a bag and for each patient, after obtaining informed consent, a paper is removed randomly and without replacement, and based on the letter written on it, the desired intervention is performed for the patient. In addition, interventions A (letrozole) or B (clomiphene) are determined by a lot, Blinding description: This study is performed double-blind, the participants, and the analyzer do not know the type of treatment. The participants, because of placebo usage, do not know the type of their treatment. Also, the analyzer does not know about the treatment group codes in the SPSS datasheet. 3 Female Infertility. Intervention 1: Intervention group:Patients receive letrozole 2.5 mg daily for 5 days from the third day of the menstrual cycle. Intervention 2: Control group: People receive daily placebo for 5 days from the third day of the menstrual cycle. Yes - There is a plan to make this available What will be shared: All data is potentially shareable after unidentified participants. When: After manuscript published To whom: No limitations Conditions: The data is only available to the project manager, Dr. Pakniat, and any analysis must be done with her opinion. Where to obtain: Dr. Pakniat How to obtain: Any request must be made in writing and accompanied by a proposal with an ethics code under the supervision of Dr. Pakniat Comments: