We know that there is a progressive loss of egg (oocyte) quantity and quality that occurs with female aging. The end result is a steady increase in the incidence of infertility, chromosomal abnormalities and pregnancy loss from age 20 to 35 and a more rapidly increasing risk of infertility thereafter. Egg freezing may allow women to have an opportunity to have biologic children later in life.
In contrast to sperm or embryo freezing, successful egg freezing has been elusive and relative difficult to accomplish until recently. This is because the egg contains much more water than any other cell type and when it is slowly frozen, ice crystals can form within the egg, severely damaging or destroying the egg. Using a new “flash freezing” process, called vitrification, the eggs can be successfully frozen after they are rapidly immersed in liquid nitrogen, minimizing freeze damage to the eggs.
The American Society for Reproductive Medicine (ASRM) published guidelines for egg freezing in Fertility and Sterility (Volume 99, Issue 1, Pages 37-43, January 2013). The guideline states that “No increases in chromosomal abnormalities, birth defects, or developmental deficits have been noted in the children born from cryopreserved oocytes. This technique should no longer be considered experimental.”
How successful is egg freezing?
Egg freezing is a relatively new procedure. Worldwide, there have been several hundred births reported to date utilizing frozen eggs. The rate of birth defects or chromosomal abnormalities appears to be comparable to that of the general population. Approximately 70% of eggs will survive the freezing process and about 40% of the eggs will be fertilized when thawed. The pregnancy rate depends on the woman’s age at the time her eggs were frozen. The pregnancy rate using frozen eggs ranges between 30-50% and is not that much different than using fresh eggs. Success rates appear to be significantly lower for women who freeze their eggs after the age of 38.
Who is a candidate for egg freezing?
There are 50,000 reproductive – aged women who are diagnosed with cancer each year. Many of them require surgery, chemotherapy and/or radiation treatments which may destroy their eggs and cause infertility. Egg freezing before beginning cancer treatment can help them preserve their fertility.
For married or single women with a male partner, conventional IVF and embryo freezing is an alternative to egg freezing
- “Social Egg Freezing” for women who want to postpone having children
Many women are delaying the age of their first pregnancy, increasing their risk of being childless as they get older. This is because there is an age related decrease in the quantity and quality of their eggs. Proactive egg freezing at an earlier age, when the best eggs are produced can provide women with the “reproductive autonomy” to have children with their own eggs when they are ready. Egg freezing eases the pressure to have a child just because the biological clock is ticking.
- Couples with religious or ethical objections to freezing embryos
Some patients may have religious or moral objections to freezing excess embryos during their IVF cycle. Other women who deliver after IVF face the dilemma of what to do with the frozen embryos if they are no longer needed. In such cases, fertilizing only 2 eggs and freezing the remaining unfertilized eggs for later use, if necessary, may circumvent the moral dilemma of banking frozen embryos.
What can I expect during an egg freezing cycle?
The usual process involves fertility hormone injections (gonadotropin injections) for about 10 days to stimulate the development of several eggs (very similar to a typical IVF cycle). The eggs are then removed from the ovary during a short surgical procedure. The procedure, done in our office, takes about 5 minutes to complete, and is performed using transvaginal ultrasound and mild intravenous sedation. Expect to go home about 30 – 60 minutes after the procedure. The eggs will be taken to the laboratory and frozen. After freezing, the eggs will be transferred to a long term storage facility where they will remain until they are needed