The technique requires the female partner to undergo ovarian stimulation with the infertility medications so that many mature eggs develop. These eggs are then aspirated via the vagina using vaginal ultrasound and incubated under precise conditions in the embryology department. The semen sample is prepared by centrifuging or spinning the sperm cells via a special medium. This separates active sperm from most of the dead sperm. After that embryologist picks up the single active/live sperm in a glass needle and injects it directly into the egg.