Egg Freezing (Oocyte Cryopreservation)
Egg freezing, clinically known as oocyte cryopreservation, is an advanced reproductive technique that allows women to harvest and preserve their mature eggs to protect their biological fertility potential for the future.
Because ovarian reserve and egg quality naturally decline with age, egg freezing serves as a reliable medical option for women delaying pregnancy for career, personal, or educational milestones, as well as those facing gonadotoxic medical interventions (such as chemotherapy or radiation) or carrying genetic risks of premature ovarian insufficiency (POI).
Steps of the Egg Freezing Procedure
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Ovarian Stimulation: Beginning at the onset of the menstrual cycle, hormonal medications are administered to gently stimulate the ovaries. This enables multiple follicles to mature concurrently rather than the single egg produced in a typical cycle. Progress is closely tracked through serial ultrasound scans and hormone assessments.
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Egg Retrieval (OPU - Follicular Aspiration): Once follicles reach optimal size, a trigger injection is administered. Roughly 36 hours later, the eggs are collected via transvaginal ultrasound guidance using a fine aspiration needle under light sedation. The procedure is painless, minimally invasive, and takes around 15–20 minutes.
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Vitrification (Ultra-Rapid Freezing): The retrieved oocytes are evaluated in the embryology laboratory, and mature eggs (Metaphase II) are prepared with cryoprotectant media. They are instantaneously flash-frozen using vitrification technology and placed into liquid nitrogen tanks at -196°C, eliminating cellular ice crystal damage and yielding survival rates exceeding 95% upon thawing.
Clinical Considerations and Success Factors
While egg freezing cannot provide an absolute guarantee of a future pregnancy, reproductive success is directly correlated with the patient's age at the time of freezing and the total number of mature oocytes stored. Freezing eggs earlier in life significantly enhances the probability of live births later on. Personalized consultations and ovarian reserve testing provide essential guidance for timely planning.
