Oocyte Cryopreservation - Vitrification

Oocyte Cryopreservation - Vitrification

Oocyte vitrification is a revolutionary new rapid freezing technique for eggs and embryos which increases dramatically their survival rate. It is a very simple procedure and requires practically no programmable freezing equipment.

Human eggs have high water content and are therefore extremely fragile and sensitive to all freezing procedures. Conventional controlled rate slow-freezing methods do not always succeed because they allow some intra-cellular ice crystal formation that causes some damage to embryos, and severe damage to most eggs, render them unusable. However, vitrification avoids the damage caused by crystal formation inside the cell increasing dramatically their survival rate.

Egg Vitrification Process

In the process of vitrification an oocyte is placed in a very small volume of a super high concentration of antifreeze medium (DMSO and ethylene glycol) for brief period of time, and is then cooled at an extremely rapid rate. The fast freezing eliminates the formation of ice crystals in the oocyte. The water inside the cell just instantaneously super cools into a solid with no ice crystal formation. With conventional “slow freezing,” the temperature of the egg and embryo goes down at precisely 0.3°C per minute.

With vitrification (using four times the concentration of antifreeze, or cryoprotectant) the temperature is dropped at 20,000 degrees °C per minute, which is 70,000 times faster. At that speed of cooling, and at that concentration of antifreeze, ice crystals simply cannot form. The egg survival rate is approximately 90%. Subsequent to the vitrification, the oocytes/embryos are stored in liquid nitrogen until such time as it is to be thawed and fertilized or transferred.

Oocyte Vitrification Risks and Limitations

However this method is not quite as simple as it might seem. The high concentrations of cryoprotectant, even for a few minutes, could be toxic to cells. Therefore, the eggs and embryos must first be placed in lower concentrations of antifreeze and sucrose in order to draw some water out of the cell and then left in high concentrations only for less than a minute before instantaneous freezing. During thawing the embryos and eggs, must be instantaneously warmed, immediately taken out of the high concentration of antifreeze, and then placed into a solution with lower concentration, in order to avoid antifreeze toxicity. The whole process requires more skill than conventional freezing, but it is faster, cheaper, and most importantly, avoids almost all freezing damage to either eggs or embryos.

Who can benefit from Oocyte Vitrification?

Such a reliable method of egg and embryo freezing gives the IVF program much greater ability to avoid dangerous multiple pregnancy, and makes scheduling for many procedures like egg donation simpler for the patient (oocyte banking). In addition this dramatic new technique offers hope to women of reproductive age, especially:

  • Young women who want to preserve their fertility for the future if they wish delay childbearing, but not lose their fertility as they age. With vitrification eggs as well as embryos are reliably preserved so the pregnancy rate is no different than if the embryos or eggs had never been frozen.
  • Women who want to freeze their eggs because they haven’t found a partner yet. As a woman gets older her fertility declines and the rate of spontaneous abortion rises. Moreover the risks of chromosomal abnormalities are higher in older women.
  • Women who are diagnosed with cancer and want to preserve their healthy oocytes before starting radio/chemo therapy. In this way they preserve their ability to start a family in the future.
  • Women who want to freeze their embryos after an IVF cycle for a future use.
  • Women with premature ovarian failure.


EMBIO MEDICAL CENTER is pleased to offer a breakthrough service for women interested in preserving their fertility for the future. Through the practice of cryo-preservation—or egg freezing—women now have the ability to freeze and store their eggs for future use.

Egg freezing for fertility preservation can benefit a broad range of women - from cancer patients undergoing chemotherapy or radiation to women who anticipate starting or adding to their families later in life.

While a woman's uterus is able to carry a pregnancy to term well into her forties, the decline in egg quality makes the likelihood of a successful pregnancy significantly lower as one's age advances into their early forties. As a result, over 10,000 European women per year are forced to turn to egg donation in order to conceive. Egg freezing provides the opportunity for women to become their own donors earlier in life. Through its partnership with Extend Fertility, EMBIO MEDICAL CENTER applies technology that replaces the fluid with molecules that make the egg less vulnerable to freezing and more viable for fertilization once they are thawed.

Women interested in exploring the option of egg freezing contact EMBIO MEDICAL CENTER for more information.

Cancer Survivors

Being diagnosed with cancer is tough enough to deal with. But if you want to have a child, you may feel an added level of anxiety. Family-building options are available after cancer treatment. The earlier you understand what those options are, the greater your chances for preserving your fertility.

Treatment is available for couples who have been diagnosed with cancer. It is important that you raise this issue with your treating doctor early in the process. It is best to see a fertility specialist early in your evaluation. However, post-treatment options are also available.

For women:

  • Radiation and chemotherapy can damage eggs.
  • If appropriate, eggs can be removed from the ovaries before treatment and in vitro fertilization can be performed. The resulting embryos can be frozen for use after treatment.
  • If eggs have been damaged during cancer treatment, egg donation is an excellent option for many women.

For men:

  • sperm can be frozen before treatment begins.
  • in vitro fertilization with an advanced technique to help sperm get into the egg (ICSI, or intracytoplasmic sperm injection) is a possible option after sperm freezing.
  • if sperm production has been affected by treatment, sperm donation is another option.

At EMBIO MEDICAL CENTER , we understand the emotional impact of being diagnosed with cancer, as well as the added concerns about building a family. We are here to help you understand your options, and will see patients diagnosed with cancer on very short notice.

Please call 0030-6973882674 to schedule an appointment with Dr.Paraschos.

Also read:

Personal Egg Banking (Elective Oocyte Cryopreservation)

EmBIO fertility specialists will be glad to guide you for your fertility treatment.

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