Successful conception is in large part due to the quality of a woman’s eggs. As women age, egg supply decreases and quality suffers. For a variety of reasons, including later marriage age and medical conditions such as cancer diagnoses and anticipated treatment, this technology can help women and couples increase their chances of having a child later, when the time is right for them.
Egg freezing (oocyte cryopreservation) is a reproductive technology in which a woman’s mature eggs are removed from her ovaries, frozen and stored. When she decides she is ready to try to become pregnant, the eggs are thawed, fertilized and implanted in her uterus.
Until recently, the pregnancy success rate with frozen eggs was low, but recent advances in preservation and laboratory techniques have revolutionized this assistive reproductive technology. Previously, eggs were cooled slowly; now they can be frozen in a fraction of a second. In addition, a new cell culture system protects the eggs from damage during both the freezing and thawing processes. Ice crystal formations, just like the ones on ice cream in the freezer, are a thing of the past.
These new developments have enabled our fertility specialists to give patients much better results. The numbers are very similar to fresh egg pregnancy rates.
Women who freeze their ages at, for example, age 35, will have the same rate of pregnancy at age 40 (with her eggs that were frozen) as if she were 35.
This technology is still considered experimental by the American Society for Reproductive Medicine, but we are confident there is sufficient clinical data to justify its use for women who want to delay child-bearing. Of course, patients are thoroughly evaluated, as they would be for any other treatment or procedure.
Two weeks of injected hormones stimulate the ovaries, encouraging the body to produce several mature eggs in a single cycle instead of one or two eggs per cycle. The eggs are retrieved through the vaginal wall with a long needle.
When the woman is ready to start her family, we thaw two or three frozen eggs and fertilize them with her partner’s sperm in the laboratory. The fertilized eggs (zygotes) are implanted into the woman’s uterus with faith that at least one will become an embryo, and the embryo a fetus, and the fetus a baby.
An advantage of oocyte cryopreservation, for some individuals, is that you can prolong your fertility while avoiding the ethical controversy of embryo freezing. Freezing an egg is not the same thing as freezing a fertilized egg. A young woman facing chemotherapy and/or radiation for treatment of a life-threatening disease, or who has a chronic condition that requires medication that negatively affects fertility, can take advantage of this opportunity without any moral dilemma. Fortunately, cancer treatments are now so successful that many young people with cancer will beat it and go on to live full lives. With that reality, having a family should not be a fantasy.