Oocyte cryopreservation, also referred to as egg freezing, is now an option provided at our offices in Glendale and Los Angeles, CA, for women who desire to preserve their fertility. At Pacific Fertility Center, Dr. Vicken Sahakian, Dr. Michele Evans, and Dr. Yvonne Yanqing Han can help you determine if this option is a fit for your goals and lifestyle.
Why Freeze Your Eggs? Women may wish to preserve their fertility if they are going to undergo cancer treatments that may decrease their future fertility potential. Others choose to freeze eggs if they are not ready to have children, but want to have the option to use their own viable eggs if they have problems conceiving in the future.
The two most common methods of fertility preservation for females are embryo freezing and egg freezing. As of the past couple of years, there is more data that suggest that egg freezing is improving as a technique and is an option we can offer patients who are not inclined to freeze embryos. In the more recent literature, several studies have reported better post-thaw egg survival, fertilization, and pregnancy rates with egg freezing compared to past research and for this reason, a renewed interest in egg freezing has occurred.
Understanding the Process
The process of freezing the eggs involves the patient administering injections in order to mature more eggs than in a natural cycle, frequent monitoring in a fertility clinic using ultrasounds and blood work, a procedure to harvest the eggs, and the actual procedure to freeze the eggs. There are two methods used to freeze eggs, the slow-freeze method and a faster method called vitrification. It is with the latter that we have seen better pregnancy rates and therefore this is the method that we use. The eggs remain frozen until a pregnancy is desired, at which time the eggs are removed from the liquid nitrogen and warmed.
Most data, taken women under the age of 38, from randomized controlled trials have concluded that using frozen eggs is equivalent to using fresh eggs when comparing pregnancy rates and/or live birth rates. Despite frozen eggs having pregnancy success rates similar to fresh eggs in some studies, there remains a limited number of established pregnancies and deliveries derived from frozen eggs compared to frozen embryos. This is the main reason why egg freezing is still considered experimental by the American Society of Reproductive Medicine when done for elective reasons and should be performed under the auspices of an investigational protocol.
In the small number of studies that have been performed looking at babies derived from frozen eggs, there have been no increases observed in the number of abnormal or stray chromosomes. One follow-up of 13 children resulting from frozen eggs failed to reveal any abnormalities in the chromosomal composition, mean age at delivery, mean birth weight, or organ formation. In another 3-year follow-up study of 16 children born post egg freezing, one case of a heart defect was noted but there was no evidence of any intellectual or developmental deficits in any of the children.
Over the past couple of years, there have been a number of randomized controlled trials demonstrating that using frozen eggs is equivalent to using fresh eggs when comparing pregnancy rates and/or live birth rates.