What might a mindful career-oriented 36-year-old woman have in common with a 22-year-old just diagnosed with an unusual cancer and scheduled for radiation or chemotherapy treatment?
- Both may want to carefully chart their course of family planning.
- Both face the loss of their ovarian egg reserves: one from the damaging chemotherapy, the other from age.
- Both may be considering oocyte (egg) freezing.
The idea that a woman can undergo a standard IVF procedure and then freeze individual eggs, instead of having her oocytes inseminated and then frozen as an embryo, is a notion that is capturing the imagination of grandmothers, women and doctors alike. So much so, dozens of infertility clinics are boasting egg cryopreservation as a new service even though most qualify it as "experimental". Indeed, egg freezing is simply too new, and it has not shown the success rates necessary for widespread marketplace acceptance. This procedure is not a panacea or an insurance certificate for everybody. However, it can be a viable option for women who are aware of its limitations.
What is most important is a patient's absolute understanding of the challenges of egg cryopreservation. To say women's oocytes are much more difficult to freeze than male sperm is an understatement. A good quality female egg is essentially a pin head-sized globule of fluid plus the necessary DNA to carry new life into being. It is this sac of liquid that must be carefully drained and then filled with anti-freeze to help the egg freeze and thaw. Accomplishing this without damaging the microcosm of genetic material, as delicate as a spider web, is the main hurdle. When egg quality is compromised, a myriad of problems ensue: failure to fertilize or implant, miscarriage and birth defects. The race to offer egg cryopreservation was initially fueled by favorable research results from a study that used subjects in their early 20s, and which resulted in >50% chance of a live birth. Yet with only 7 subjects, that study is not statistically significant. In subsequent studies that used women in their early 30s, the success rate dropped below 25%. Currently, most U.S. clinics pioneering this procedure predict only an 8-10% chance of live birth. Also, a side effect of freezing is the hardening of the egg's outer membrane, known as the zona pellucida, making sperm penetration difficult. However, this is overcome by using ICSI (intracytoplasmic sperm injection). Those requesting this service need to have all of the facts before making a choice. In particular women in their mid- to late-30s, who tend to be the most enthusiastic candidates, need to weigh other options with higher proven success rates.
We at Pacific Fertility Center in San Francisco share an understanding with much of the reproductive medical community that the egg freezing procedure may be the right choice for the right person, but only with a full understanding of its limitations. This will be our approach when we start offering egg cryopreservation to our patients later in 2004.
Learn even more about egg freezing from our new resource that can provide you all the information you want to know about freezing your eggs.