Fertility Preservation by Egg Banking (Egg Freezing)
Compared to embryo freezing, egg freezing (oocyte cryopreservation) is a relatively new technique of fertility preservation. Like an embryo freezing cycle, an egg freezing cycle resembles an IVF cycle for the most part. An egg freezing cycle starts with ovarian stimulation and ends with egg retrieval.
During the ovarian stimulation phase, the patient self-administers daily hormone injections to stimulate her ovaries. While only one mature egg is ovulated for possible fertilization in a natural menstrual cycle, ovarian stimulation encourages the ovaries to produce multiple mature eggs. Once mature, those eggs are retrieved from the ovaries with a thin needle, which is inserted through the vagina under ultrasound control, while the patient is asleep under intravenous sedation administered by an anesthesiologist. The egg retrieval takes only a few minutes.
Here, the retrieved eggs are not fertilized with sperm, but immediately cryopreserved (frozen).
Egg freezing is technically more challenging than embryo freezing. One reason is the large size of a mature egg cell, which is the largest cell in the human body. Oocytes (eggs) are more difficult to freeze and thaw compared to embryos, which are made up of much smaller cells. These technical complexities add to the uncertainties surrounding future pregnancy chances after egg freezing.
Risk-Benefit Considerations of Egg Freezing
If performed for cancer patients, egg freezing is no longer considered experimental by professional organizations in the field, including the American Society for Reproductive Medicine (ASRM). This designation may require some explanation: Adequate outcome data on egg freezing are still lacking. However, the alternative for cancer patients is loss of ovarian function with no chance of future pregnancy with use of their own eggs. The risk-benefit consideration under such circumstances, therefore, clearly favors egg freezing in young cancer patients, whatever future pregnancy chances may be, because even a small chance of pregnancy that egg freezing may offer is better than no chances at all.
Egg freezing for social reasons, on the other hand, is considered still experimental. For women who want to freeze eggs so that they can focus on life’s other priorities while safeguarding their current fertility, the risk-benefit analysis is still unclear, because the lack of long-term outcome data makes it difficult for even expert physicians to offer guidance on how many eggs should be cryopreserved.
Mass and social media recently “discovered” the subject after some highly visible tech companies announced that they would offer to their employees insurance coverage for egg freezing. Unfortunately, coverage of this highly complex issue by the media has been very superficial, often driven by talking points provided by public relations firms for a rapidly developing “industry” around fertility preservation.
CHR strongly objects to the rapid commercialization of social egg freezing, characterized by excesses like “egg-freezing parties.” We consider social egg freezing to be an excellent option for carefully selected and well informed women. Egg freezing, however, is always a second-best option after spontaneous conception at younger years, and given the still-experimental nature of the procedure, thorough counseling by a qualified physician is crucial.
CHR also strongly believes that the current status of egg freezing as an experimental procedure is appropriate, and that this fact should be openly communicated to all women considering this procedure.
Who May Benefit from Egg Freezing
Egg freezing may be a good option for medically indicated and social fertility preservation. Who may benefit directly depends on the pros and cons of egg freezing:
- Unlike embryo freezing, egg freezing does not require sperm;
- Egg freezing usually takes a few weeks to complete;
- Most women will need more than one egg freezing cycle in order to accumulate enough eggs to have a reasonable chance of future pregnancy.
Because egg freezing does not require sperm, egg freezing is a good option for women who do not have a committed life partner to produce embryos with. Because of time limitations, egg freezing may not be possible in cancer patients who must immediately start life-saving treatments. For these patients, ovarian tissue freezing, either alone or in combination with limited egg freezing, may be a better choice, since ovarian tissue freezing, a surgical procedure, can be performed on a very short notice.
Egg freezing may also be an attractive option to young women who discover that they may be at risk of premature ovarian aging (POA). About 10 % of all women develop POA when their ovaries prematurely lose the ability to produce healthy eggs.
Losing fertility potential with advancing age is normal. However, in women with POA this loss happens earlier than it is normal. CHR investigators developed a patented risk detection algorithm, which allows young women to determine their risk of developing POA. If diagnosed with risk toward POA at younger ages (currently the diagnosis is usually made at much older ages), women gain new options: They can either decide to have children at a younger age or, when this is not possible or desirable, freeze eggs (or ovarian tissue) when they are still young. The younger the patient when her eggs are frozen, the more “fertile” they are.
How Many Eggs to Freeze
How many eggs a woman should freeze in order to achieve a reasonable chance of future pregnancy is not well established yet, and will depend on her age and ovarian function. We recommend freezing of at least 20-25 eggs for young women for every future pregnancy they are planning for. Because an egg’s potential to fertilize, develop normally and lead to a healthy pregnancy declines precipitously with age, the older a woman at the time of egg freezing, the more eggs she will have to freeze. Therefore, older women may need more than 25 eggs to achieve a pregnancy in the future.
This means that most women will need more than one egg freezing cycle. Since older women produce fewer eggs per egg freezing cycle, they may need many more cycles. Recognizing this fact, CHR has established a Multiple Egg Freezing Cycle Program, which offers a discounted package price for four (4) egg freezing cycles. CHR physicians will counsel all patients based on their specific circumstances and needs.
Read more about Fertility Preservation
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Last Updated: November 15, 2014