Follicular aspiration, or egg retrieval, is a transvaginal ultrasound-guided procedure in which oocytes, or eggs, are retrieved from the follicles. Follicles are structures in ovaries, which grow in the first phase of the cycle. Their rupture and release of the egg marks the time of ovulation. .

On the day when the follicular aspiration is scheduled, a patient must fast for at least 6 hours prior to the procedure. Emptying the bladder right before the procedure is immensely important. The procedure is performed transvaginally, under the ultrasound control. The vagina is rinsed with a special disinfectant and ultrasound probe is introduced. A needle, connected to dishes for retrieving the contents of the suction via a system of plastic tubes, is introduced through vaginal wall and into the ovary. Then the aspiration follows, i.e. suction of follicular contents which is fluid containing an oocyte (egg). Although a needle is quite long and may cause fear with the patients, the depth of the insertion for superficial follicles is no more than 5-10 mm. The sticking of a needle is mildly painful and patients who opt for procedure with no analgesia usually have no problems.

A biologist immediately checks the contents of the provided test-tubes under the microscope and announces the number and quality of eggs retrieved.