After the completion of ovarian stimulation and when the follicles have reached the final stage of maturation, oocyte collection is scheduled. The collection is performed with ultrasound guided trans-vaginal puncture of ovarian follicles. The doctor uses a puncture needle to “penetrate” one by one the ovarian follicles and aspirates the contained fluid. The follicular fluid is examined by the embryologist for the presence of oocytes. When an oocyte is identified, it is collected and placed in appropriate culture media. The total number of oocytes is announced by the embryologist at the end of the procedure. Although oocyte collection is a painless and quick procedure, it is performed with the administration of analgesia.