Egg freezing (or mature oocyte cryopreservation) is a fertility preservation method used to increase a woman’s chances of having a baby. Egg freezing is a process of harvesting woman's eggs from their ovaries and freezing them for later use when they are ready to be a mother. When eggs are frozen, the quality and ‘youth’ of the eggs are preserved. Women get the benefit of an egg that was frozen during their peak fertility.
In order to retrieve eggs for freezing, a patient undergoes the same hormone-injection process as in-vitro fertilization. The only difference is that following egg retrieval, they are frozen for a period of time before they are thawed, fertilized and transferred to the uterus as embryos.
While the chance of conceiving is the highest around the age of 25, this chance decreases gradually towards the 30s, and after the age of 35 it is significantly lower than the younger women.
While it decreases even more in their forties, it becomes almost impossible to get pregnant after the age of 45. With age, the quality of the eggs decreases, accumulate more DNA damage. This is reflected in lower fertility rates and higher rates of miscarriage as women age.
1-Egg Freezing Assessment & Initial Consultation
After initial consultation and necessary tests the treatment shedule will be decided. If you provide all your recent tests and medical reports by mail or Whatsap we can decide on your egg freezing protocol before coming to Istanbul.
2-Ovarian Stimulation and Clinic Visits
The primary goal of ovulation induction treatment is to stimulate the ovaries hormonally in order to produce more than one egg.
Ovarian stimulation typically begins on days 2-3 of the menstual period. To ensure the ovaries are responding well to the medications, a number of office visits for transvaginal ultrasounds typically 3-5 times is needed. These monitoring appointments can be done at your home city at a local clinic capable of fertility monitoring for those traveling from out of İstanbul. Stimulation period takes roughly 10 days.
A trigger medication is given by injection (human chorionic gonadotropin-hCG) to promote the final maturation of eggs once they reach 17-18 mm size. This hCG acts as the woman's natural LH peak and ovulation is normally triggered. Egg collection is performed approximately 35-36 hours later.
Oocyte pick up (OPU) is performed easily and comfortably by vaginal ultrasonography. The patient lies in gynecological examination position under light anesthesia and is covered with sterile drapes. The ultrasound probe is placed in the vagina. The needle passes through the vaginal wall without any cuts or stitches so recovery time is usually minimal. When mature follicles are identified in the ovary, the follicles are entered under the guidance of this needle. The egg in the follicular fluid is taken out with the help of a special aspirator. All the follicular fluids are collected and given to embryology lab. OPU lasts approximately 5-15 minutes. After OPU, the patient is taken to her room and rests for a while. The number of eggs retrieved depend on woman’s age, history, fertility diagnosis, ovarian reserve, and response to medications. Immediately following your retrieval, your follicular fluid will be taken to our embryology lab to search for and isolate your eggs in preparation for freezing.
5-Freezing the Eggs
In our clinic we use a flash-freezing technique called vitrification which dehydrates and freezes the eggs instantaneously providing the best survival rate upon thawing. Whereas in conventional cryopreservation the concentration of the cryoprotectant is low and the cooling rate is very slow to avoid ice crystallization, vitrification is an ultrarapid cooling technique that requires a high concentration of cryoprotectant. During vitrification, cryoprotectants are added at a high concentration while the oocyte is at room temperature. To further protect against ice-crystal formation, an extremely rapid rate of cooling is used. To achieve these rapid cooling rates, oocytes are placed in small volumes of cryoprotectants and exposed directly to liquid nitrogen at -196 0C. With this method no ice crystals form that can damage the cells or the tissues. After being frozen, the eggs are moved into long term storage tanks and are available for your use whenever you’re ready.
How many eggs should be stored to achieve a pregnancy?
The studies show that, egg thaw rates are 75% and fertilization rates 75% in women up to 38 years of age. Thus, when 10 eggs are frozen, 7 are expected to survive after thawing, and 5 to 6 are expected to fertilize and become embryos. Usually 1-2 embryos are transferred in women up to 38 years of age. Implantation rate is 60-70%, therefore it is recommended 10 eggs be stored for a better pregnancy rate. Most women 38 years of age and under can expect to harvest 10-20 eggs per cycle.
What is the ideal age?
Although the optimal age for freezing eggs is between 31-35, many requests for oocyte cryopreservation come from women aged 36-40 years. The number of eggs that are retrieved for freezing is dependent upon the woman’s age, but the age is not the only single factor. The ovarian reserve of women between 35-40 years are not equal. Although women less than and equal to 40 will have better success, studies have shown that egg freezing is cost-effective until age 38. Although cryopreserved oocytes from women between 38-40 years age group will result in fewer pregnancies, these women may still benefit given the accelerated age-related decline in fertility after the age of 40 years. Moreover, the decline in pregnancy potential per oocyte can be compensated by additional cryopreservation cycles. Therefore all women with normal hormone levels under 40 can consider egg freezing if they plan to delay their pregnancy.
What is the chance of woman with diminihed ovarian reserve (early menopause) in young age?
Although the number of eggs of these women is low, their eggs are of high quality because they are young. When these eggs are frozen and stored, even if the age of the woman increases, as the eggs are young, the chance of getting pregnant and resulting in healthy babies is higher in IVF treatments after thawing.
What happens when the woman ready to get pregnant?
After meeting with the doctor to ensure that she is healthy and ready for carrying a pregnancy she will begin taking medicines on the second day of the period to prepare the uterus for pregnancy. When uterus is ready for embryo transfer the eggs are thawed and injected with sperm through a process known as ICSI (Intracytoplasmic Sperm Injection). The resulting embryos are then transferred into the uterus when they are either 3 days or 5 days old. Any extra embryos can be frozen and stored.
After embryo transfer hormones are continued to support early pregnancy. 10-12 days later depending either 3 or 5th day of embryo transfer pregnancy test is performed. 2 weeks after the positive test the gestational sac and embryo can be seen on ultrasound.