Egg Cryopreservation

Decline in pregnancy rates due to aging is primarily caused by reduced quality of egg with aging. If a woman consents to cryopreservation of her eggs, she may have chance of pregnancy whenever she feels ready, even when she is 50. Recently, egg cryopreservation offers a chance for young women who want to delay pregnancy especially due to career.

Who Can Have Eggs Frozen?

Legal criteria for oocyte cryopreservation in our country are as follows: protective of reproductive capacity before cancer treatment, such as chemotherapy and radiotherapy, which may lead to infertility; surgical procedures that may cause loss of ovarian function; women with low ovarian reserve who have not given birth or have family history of early menopause, provided a health report is issued and signed by three physicians.

Does Cryopreservation Damage Eggs?

Oocyte cryopreservation does not cause cell death. Freezing pauses intracellular movement and cellular metabolism for a short period of time. Death of a cell is caused by ice crystals that form inside the cell. Current freezing technique (vitrification) prevents formation of ice crystals inside the cells and frozen cells can maintain viability in liquid nitrogen for many years. .  

How Is Oocyte Cryopreservation Performed?

Ovaries are stimulated or induced in a controlled manner through a medication therapy that lasts for 10 to 14 days in average and next, oocytes are picked up under anesthesia. The picked up oocytes are frozen using vitrification (quick) freezing method. Consent form must necessarily be signed by the person before the cryopreservation. Documents and reports that mention the ground of freezing should be attached to the form. Frozen sex cells are recorded and stored in storage containers filled in with liquid nitrogen at -196 ℃.

Are Babies of Pregnancies Achieved with Cryopreserved Eggs Healthy?

Egg freezing does not damage the baby. First twin pregnancy with frozen oocytes was achieved in 1986 and more than one thousand healthy babies without any congenital anomaly were born thereafter. Studies did not reveal out a significant difference between frozen oocytes and fresh eggs in terms of birth of living newborn infants and obstetric (diabetes, hypertension, premature birth, anemia etc.) and perinatal results. Freezing the embryos derived from eggs that are frozen with vitrification has no negative effect on birth rates of healthy newborn infants.

How Long Can Frozen Eggs Be Stored?

Storage period is 1 year (it can be extended each year up to 5 years, provided consent is obtained from the patient; approval of Ministry of Health is required beyond 5 years). If the person with frozen eggs decides not to use the eggs and does not want to continue storage, the only option is disposal of these eggs. If so, it is necessary to visit the in vitro fertilization center and submit a letter of request that is signed by the person and specifies the reason of disposal. Next, Ministry of Health is notified and eggs are disposed.