Female Fertility Preservation

By the early 1990s, freezing (cryopreservation) of embryos was an important and successful aspect of IVF treatment. However, it took another 10 years to make egg freezing a practical option. Surprisingly, it was not an advancement in cryotechnology that changed the situation. It was the discovery that intra-cytoplasmic sperm injection (ICSI) was needed to fertilize frozen eggs. With ICSI, individual sperm are injected into eggs, rather than letting the eggs fertilize naturally in the lab. This is a classic example of one technology building upon another.

Currently, with fast-freezing techniques (vitrification) and ICSI, it appears that fresh and frozen eggs perform equally well. This opens the door for women who need or want to preserve their fertility if conceiving is likely to be delayed.

Egg freezing is useful in three situations:

1. Women about to undergo chemotherapy for cancer
2. Women who anticipate delaying childbearing for personal or professional reasons
3. Egg banking

Cancer Patients

Most chemotherapy protocols can destroy a woman’s eggs leaving her with few or no eggs at all. In most cases, there is enough time to freeze eggs before the woman is exposed to these toxic agents. Most of the evidence shows that this is safe, even for breast cancer patients. Some women with acute leukemia cannot wait very long, so it is imperative to start the process quickly. 

Planned Delayed Childbearing

If a woman in her early thirties is fairly sure she will not have children soon, it is wise to think about egg freezing. The dilemma for these women is that they likely will get married and have children. But if they wait too long, their egg numbers drop, and the chance of producing chromosomally abnormal eggs rises. At some point, a woman has to decide when it is right for them to do this.

Egg Banking

Another consequence of delayed childbearing is the rising demand for donor eggs. For many years, all the eggs from a donor cycle were used by the intended mother. This created a lot of waste since oftentimes, the donor produced more embryos than the recipient could use. In addition, this approach limits the availability of suitable donors for women who are looking for specific ethnic or other features in a donor. Egg banking allows clinics to store eggs from young donors, and distribute them in smaller numbers. This reduces waste, reduces the cost to the recipient, and increases the "inventory" of suitable donors.

From our experience, these frozen donor eggs perform similarly to fresh eggs. There are two possible disadvantages of working with banked eggs. First, the eggs tend to be sold in batches of 5 or 6. These typically create one or two embryos. If the treatment fails, the recipient typically must purchase more eggs, and the resulting total cost is similar to working with a “fresh” donor. Still, at least they have attempts to result in a viable pregnancy, so many patients save around 50% of these costs. Secondly, the majority of the eggs a woman produces do not result in babies. Thus, by chance, a vial of frozen eggs could contain eggs destined not to become a baby. There is no way to control this.

The Process

The process is similar to routine IVF, it begins with screening. Women should have a blood test for AMH. This hormone roughly predicts how a woman will respond to ovarian stimulation. Women with AMH levels under 1.5 may have trouble producing 10 eggs at one time and may require extra attempts. Women should undergo infectious disease and genetic screening.

Daily hormone injections are administered to produce multiple eggs. In most cases, women commence this treatment with their periods, or after stopping birth control pills. For women with acute cancers, it has been shown that drugs can be started at any time in the cycle with adequate results.

Using these drugs requires 2 or 3 office visits for ultrasound and hormone measurements to help determine how many eggs are being produced, and when they will be ready. When the woman has an appropriate number of mature follicles, she takes a final "trigger" shot to prepare her eggs for retrieval. Using light anesthesia, and ultrasound visualization, a needle is guided into the ovaries, and the follicles are aspirated. These fluids are taken to the lab to find the eggs.

Like all medical procedures, there are small sources of risk. On rare occasions, if women produce more than 20 eggs, they can experience hyperstimulation syndrome (OHSS). In this situation, women develop very enlarged and painful ovaries, and in severe cases, get liters of fluid into the abdomen. The good news is that when we see this potential during the monitoring process, we can alter the trigger shot to greatly lower this risk. The retrieval itself can cause infection or internal bleeding. With antibiotic administration, infection is almost never seen. Bleeding is also rare, and treatment employs bed rest, hydration, and pain medication. Overall, we believe the process is safe, as evidenced by the fact that many egg donors return several times to donate eggs.

Success Rates

An obvious question is how successful are frozen eggs at producing a live baby? Surprisingly, it is hard to answer this question. This is because the majority of frozen eggs have not been used yet. Most of the women who have frozen their own eggs for fertility preservation have not used them. Many of these women go on to conceive naturally, after freezing their eggs. There are two observations that help women assess this technology. Our experience with frozen donor eggs shows them to be almost as successful as fresh eggs. We have a 50% pregnancy rate with frozen donor eggs; 60% with fresh. Also, for women in their thirties, it seems to take about 10 eggs to make one baby. Thus, women should aim to collect 10 or more eggs, if possible. This is one reason not to delay the process if it is clear that getting pregnant is not going to happen in the near future.

Costs

Costs vary widely from program to program, and especially from region-to-region. At HRC Fertility, a single attempt at egg freezing costs around $10,000, including medications. Some employee-friendly tech companies offer insurance coverage to their employees for this.

In summary, egg freezing offers women new opportunities and choices to plan their families. For cancer patients, this can provide considerable emotional support to help them through the tough months of toxic treatments. For women delaying their childbearing, frozen eggs represent a good plan, but not an infallible one. When possible, women should try to conceive when they can, and not rely solely on this technology. Finally, egg banking offers women who need egg donors a more affordable option, with some limitations.