Oocyte Cryopreservation (egg freezing) is a type of artificial reproduction technology used to preserve fertility. Many people may not have the opportunity to have children at the right time due to cancer, advanced age, or lack of a partner.
To prevent infertility post chemotherapy or ovarian function decline after menopause, women can chose oocyte cryopreservation to have children at a later time. This type of treatment is like buying insurance. The egg stays at the condition and age (biological time is stopped) that it was frozen and chances of pregnancy also stay the same. By definition, an egg is an asset, not a life. Therefore, it can continue to be frozen until the person dies and there is no time limit or risk of deterioration.
Before the procedure, drugs to stimulate egg production and follicular growth are given.
The high concentration of the drugs allows for more eggs to be produced. Besides continuous injection therapy, during stimulation, blood (hormone level) and 3D ultrasound (measures follicle volume) testing is done every few days to monitor the development of the follicles in the ovaries. Our experienced physician will analyze the data and will adjust hormonal injection concentration accordingly.
When the doctor sees that the follicles are ready, ovulation is triggered with a gonadotropin product. It initiates the release and maturation of the egg. At the same time, an appointment will be made for egg retrieval. It is imperative that the patient comes to the fertility clinic at that time. During egg retrieval, transvaginal ultrasound aspiration is used and a very thin needle is inserted into the vagina to remove all the mature eggs from the ovary. The patient is fully sedated so during the 15-20 min of the procedure no discomfort is felt.
After retrieval of the eggs, the technician will place them in a special incubator with conditions similar to the human body. Afterwards, the eggs will be frozen until it is needed. One day it will be fertilized, turned into an embryo and transplanted into the uterus. The mother will then begin her journey of pregnancy.
Cryopreservation of egg, embryo, or sperm’s latest technology: Vitrification
There are two current types of cryopreservation methods: slow freezing and vitrification. Traditional slow freezing may cause intracellular ice crystals to form when the temperature slowly drops. Hence, organelles may be harmed and survival rate decreased. Vitrification solves this problem by beginning with the placement of the cell into -196 degrees liquid for freezing. Through very rapid cooling and special medium, the formation of ice crystals is suppressed. Compared to traditional slow freezing’s 55% survival rate after thawing, vitrification survival rate after thawing is nearly 99.9%.
In the past, cryopreservation techniques were not sophisticated enough to freeze eggs. Eggs are different from embryo due to the fact that they have higher water concentration so harmful ice crystals are more likely to form through slow freezing. But in 2006, vitrification was invented and eggs, embryo, or sperm have much higher survival rates after thawing. Pregnancy rates and successful live births have therefore skyrocketed.