Today, the most effective strategy in the IVF program is 'one and done, which means that our task when performing one stimulation of follicular growth is to obtain a sufficient number of eggs and, accordingly, healthy embryos for the freezing procedure. Often such a program enables a woman to plan a pregnancy after the birth of her first child by transferring the next embryo without stimulation, moreover, such embryos were obtained at a younger age. This ensures maximum effectiveness, prevents unnecessary visits of the couple to the clinic and frequent testing. This is also important psychologically for a couple and, especially, for a woman as it saves her valuable reproductive time. Since only one follicle matures in the natural cycle (rarely two), it might contain no egg, the oocyte might be immature or not fertilized, ovulation might occur spontaneously before the puncture begins. At the same time, a woman needs frequent ultrasound monitoring of follicle growth, which creates additional intense emotional stress ("What if the follicle already ovulated?" "Will one egg lead to the embryo development?"). For that reason a procedure in the natural cycle is recognized as low-performance and has very limited application.
Transvaginal puncture (aspiration) of follicles is carried out with the aim of collecting follicular fluid with oocytes under intravenous anesthesia and lasts 20-30 minutes. After it, the patient is under observation for 1-2 hours.
During puncture in the framework of IVF, the follicular fluid is immediately transferred to the embryological laboratory. The embryologist separates the oocytes, washes them from the follicular fluid, and preliminary evaluates their degree of maturity. After that, all oocytes are placed into a special nutrient medium and transferred to an incubator until fertilization takes place 4 hours after the eggs are retrieved.