By Desireé McCarthy-Keith, MD, MPG, FACOG
Before birth, a baby girl’s ovaries contain six to seven million developing eggs. By the time she enters the world, her egg count has dropped to around one million. From birth on, she will have a steady decline in her egg supply until menopause, at which point her egg supply is exhausted and her fertility ends. This is a natural process for all women.
At the same time that their egg counts are dropping, many women are choosing to put off having children in favor of education, career or personal goals. For others, unfortunate circumstances like a sudden cancer diagnosis may force them to delay their plans for a family. And then there are women who are still waiting for Mr. Right or wish to maintain their child-free lifestyle a little longer. Women who find themselves in any of these life circumstances may consider freezing their eggs.
No medical therapy can halt natural ovarian aging, but thanks to advances in modern reproductive medicine, women can now freeze their eggs and “preserve” their fertility for later. Oocyte cryopreservation (“egg freezing”) is a medical procedure through which a woman’s eggs can be harvested, frozen, and at a later date, thawed, fertilized and transferred to the uterus as embryos. An egg freezing treatment cycle lasts approximately four to six weeks, and the technique is the same as for in-vitro fertilization. A woman self-administers hormone injections for about 10 to 12 days to stimulate egg growth. Once the eggs are developed, a needle is inserted into the ovary and the eggs are removed. Once eggs are frozen, they can be safely stored for years until the woman is ready for pregnancy.
Due to aging effects on egg number and egg quality, the best time for a woman to freeze her eggs is when she is in her mid-thirties or younger. Laboratory methods for egg freezing have improved considerably in the last 10 years, and pregnancy rates with frozen eggs may be comparable to those with fresh eggs. Pregnancy rates are not affected by the woman’s age when she returns to use her frozen eggs.
Any woman considering egg freezing should consult with a fertility specialist without delay. A simple ultrasound and blood work can determine if her egg supply is normal and if she would be a good candidate for egg freezing.