Recently, egg freezing success rates have been on the rise. Depending on the method, timing and health of the recipient during the retrieval, egg freezing may be an excellent choice for women or couples who want to have a genetically-related child, but are unsure they will be able to do so in the future. Below is a discussion of the many factors affecting the success rates of freezing eggs.
Freezing Methods
There are two options when freezing eggs: slow or fast. Slow freezing consists of initially injecting the egg with a low amount of a freezing agent and then adding to that amount at regular intervals over a period of time. This method prevents ice crystals from developing on the egg, which may destroy the eggs future ability to become fertilized or its overall viability. In the fast freezing method, the egg is injected with a high amount of freezing agent while still at room temperature and then subsequently frozen rapidly two more times. This method, too, is designed to prevent the formation of ice crystals. Rapid freezing is a relatively new procedure with less research; slow freezing is more commonly used.
Success Rates Defined
Prior to researching the success rates for the egg freezing procedure, it is important to understand the different between clinical pregnancy rates and the live birth rate. A clinical pregnancy rate refers to the percentage of women who become pregnant from using a frozen egg. This percentage is subject to a miscarriage percentage, typically 25%, that must be deducted from the overall rate to obtain the true number. Live birth rates, though, refer to the number of live births of at least one child. This number does not need to be altered to include a miscarriage percentage. When investigating clinics or specialists to use for this procedure, make sure that the success rate you are quoted is the number of live births, as it is more accurate.
General Success Rates
Success rates of egg freezing vary based on the length of time the egg was frozen, the clinic or specialist, the method of freezing used and the woman’s health. However, typical success ranges from 50-75% of live births for performed procedures.
Related Success Rates
Many reports also contain egg freezing success rates for miscarriages and birth and genetic defects. Typically, percentages of these problems occurring in pregnancies using frozen eggs are no higher than those for non-frozen egg pregnancies.
Also, egg freezing has a much higher success rate without multiple births than other procedure. Newly developed genetic testing enables physicians to check frozen eggs to see if they were damaged during the freezing process and only implant those eggs that are unharmed and viable. This procedure is not typically performed for fertilized eggs used for in vitro fertilization.
Ovarian Tissue Freezing Success Rates
Sometimes, a physician may be able to remove a portion of a healthy ovary and subsequently reattach this portion to the ovary. Success rates for this relatively new procedure are unknown, but most women report that menstruation reoccurred within three to four months of the graft procedure. The graft typically lasts from three to four years.
