When the oocytes are ready to be retrieved, another vaginal ultrasound similar to those performed to monitor follicular development is performed.

A small needle inserted in a guide attached to the ultrasonic probe is directed through the vaginal wall into the ovarian follicles.
The needle is connected to a suction pump and the fluid from each accessible ovarian follicle within the ovary is aspirated.

The aspirated liquid is transferred to the laboratory and examined microscopically to recover the eggs which will be immediately placed in a nutrient broth.