The investigators will study the immune cell subpopulations in follicular fluid of patients undergoing In-Vitro Fertilization (IVF) treatment in our clinic. The investigators will corelate the presence of immature myeloid cells to the ovarian stimulation response as indicated by follicle stimulating hormone (FSH) and number of follicles or estradiol level developed on the day of human chorionic gonadotropin (hCG) administration.