Based on the number and quality of available embryos and patient's age , one to five embryos were transferred on the day 2 or 3 after oocyte retrieval under ultrasound guidance with a CCD embryo transfer catheter (Laboratory C.C.D., Paris, France). Luteal support with progesterone 100 mg daily IM was started on the day of oocyte retrieval and was continued until the documentation of fetal heart activity on ultrasound.