What is Egg Freezing (Oocyte Cryopreservation)? Process and Success Rates

Egg freezing, medically known as oocyte cryopreservation, is the process of harvesting healthy eggs (oocytes) from a woman’s ovaries and freezing them in a high-tech laboratory environment for future use in achieving pregnancy. This procedure essentially pauses a woman's biological clock, allowing her to carry the potential of her egg quality and quantity from a peak period into the future. Assoc. Prof. Dr. Nazlı Korkmaz emphasizes that egg freezing is not merely a medical necessity but also a "biological insurance" that protects a woman's reproductive freedom and her future chances of becoming a mother in the modern world.

The Biological Necessity of Egg Freezing

Unlike men, women are born with a finite number of eggs and do not produce new ones throughout their lives. Starting from the age of 35, the ovarian reserve begins to decline rapidly, both in terms of quantity and genetic quality. By the time a woman reaches her 40s, the probability of achieving a healthy pregnancy drops significantly due to an increase in chromosomal abnormalities. Egg freezing preserves the eggs at the quality of the age they were frozen; therefore, if a woman chooses to use these eggs at age 40, her chance of pregnancy will reflect the success rate of the age she was when she froze them (e.g., age 30).

Thanks to the "vitrification" (ultra-rapid freezing) technique used in modern medicine, egg cells reach a glass-like state without the water inside turning into damaging ice crystals. This method has minimized the risk of damage during the freezing and thawing phases, increasing the viability rates of the eggs to over 90%.

Who is a Candidate for Egg Freezing?

Within the framework of legal regulations in Turkey and medical necessities, egg freezing is performed for the following groups:

1. Patients Undergoing Cancer Treatment: Treatments such as chemotherapy or radiotherapy can cause severe damage to egg cells (gonadotoxic effect). Freezing eggs before treatment preserves the chance of motherhood in the post-cancer period.

2. Women with Low Ovarian Reserve: Women who are not yet married but have been diagnosed with a diminishing ovarian reserve (independent of age) through clinical tests such as the AMH test or ultrasonography have the legal right to freeze their eggs.

3. Those with a Family History of Early Menopause: Women whose mothers or sisters entered menopause at an early age carry a high genetic risk. Taking precautions before the reserve is exhausted is of vital importance for these individuals.

4. Prior to Surgical Interventions: Operations for chocolate cysts (endometriomas) or other ovarian surgeries can damage ovarian tissue. Freezing is recommended before such operations.

5. Social Reasons: For women who wish to postpone motherhood beyond the age of 35 due to career planning, education, or because they have not yet found a suitable partner, this procedure is the safest path forward.

The Egg Freezing Process: A Step-by-Step Clinical Guide

The procedure typically spans a 10-12 day period and is identical to the initial stages of a standard IVF treatment:

• Preliminary Evaluation: On the 2nd or 3rd day of the menstrual cycle, an ultrasound and hormone tests are performed to analyze the status of the ovaries.
• Ovarian Stimulation: Personalized hormone medications are administered to encourage the ovaries to produce multiple eggs instead of just one.
• Monitoring: Every 2-3 days, follow-up appointments are scheduled to monitor the growth rate of the follicles (egg sacs) via ultrasound.
• Trigger Injection: Once the follicles reach the desired size, a "trigger" shot is administered to finalize the maturation of the eggs.
• Egg Retrieval (OPU): Approximately 36 hours after the trigger shot, the eggs are retrieved under light anesthesia via vaginal ultrasound. The procedure is painless and takes about 15-20 minutes.
• Vitrification (Freezing): The mature eggs are isolated in the laboratory and frozen in liquid nitrogen tanks at -196 degrees Celsius for long-term storage.

Legal Framework and Storage Duration

According to current regulations in Turkey, egg freezing requires a medical justification, such as a medical committee report documenting "diminishing ovarian reserve" or a cancer diagnosis. Frozen eggs are initially stored for 5 years. At the end of this period, the individual can extend the storage duration annually by submitting a written request. It is a legal requirement in Turkey that the individual must be married at the time the stored eggs are used for pregnancy.

Factors Influencing Success

The two most critical factors in egg freezing are the woman's age and the number of eggs frozen. Freezing 10-15 eggs before the age of 35 can increase the chance of a healthy live birth to over 80%. As age advances, the probability of eggs being genetically healthy decreases, so a higher number of eggs may need to be frozen to achieve similar success rates.

Frequently Asked Questions (FAQ)

1. Does the egg retrieval procedure affect virginity? The standard application is performed vaginally. However, for patients with concerns regarding virginity, the procedure can be successfully performed via an abdominal ultrasound-guided approach without damaging the hymen.

2. Does egg freezing accelerate menopause? No. Every month, your body naturally selects a group of eggs; only one grows to maturity while the others perish. Hormone treatment aims to rescue and grow those eggs that would have otherwise been lost that month. Therefore, it does not deplete your reserve or trigger early menopause.

3. How long do frozen eggs remain healthy? Theoretically, cells stored in liquid nitrogen tanks can remain structurally intact for many years (10-20 years or more). There is no technological time limit for storage.

4. How many eggs should I freeze? The ideal number depends on age. For women under 35, 8-10 eggs generally provide a sufficient chance of pregnancy. For women over 38, it is recommended to increase this number to 15-20.

5. When can I return to daily life after the procedure? Rest is recommended on the day of the egg retrieval. You can fully return to your social and professional life the following day.

6. Is there an age limit for egg freezing? While there is no legal upper limit, the success rate of the procedure decreases significantly after the age of 43-44, when egg quality drops sharply. Medically, performing the procedure between the ages of 30 and 38 is considered the most ideal approach.

The egg freezing process is one of the greatest opportunities modern medicine offers to women. Protecting your option to "become a mother" in the future reduces the pressure of time, allowing you to make freer decisions in both your career and private life.

To pause your biological clock and take the right step for your future, you can visit our clinic in Ankara for a personalized reserve evaluation and treatment plan under the guidance of Assoc. Prof. Dr. Nazlı Korkmaz.