Egg Banking of Genetically (CGH)-Tested Eggs Could Change The Face Of IVF-Ovum Donation

For more than a quarter century, medical scientists have attempted to defy the biological clock by freezing a woman’s eggs to preserve her fertility. Most of these efforts have failed. Consider the fact that since the birth of the world’s 1st “frozen egg baby” in the mid 1980’s, fewer than 1,000 such births have been reported worldwide. Compare this to more than 3 million IVF babies born in the same time period and approximately 25,000 IVF births per year from frozen embryos.
Until very recently, the reported statistical chance of a frozen and thawed egg ultimately resulting in a baby has been under 4%.

There are two major reasons why egg freezing has been such a dismal failure. The first is the fact that even in young women; more than 60% of eggs are chromosomally defective and thus non-viable, making egg freezing a hit and miss gamble to begin with. The second reason is that prior methods used to slowly freeze human eggs, caused ice crystals to form within the egg, damaging it to the point that a high percentage of frozen eggs did not survive the freezing process (let alone make it to the viable embryo stage.

In October 2008, we reported in the Journal "RBM Online" on a process that dramatically improves the frozen egg birthrate 7-8 fold. It involves identifying and selecting chromosomally normal eggs using a genetic test known as Comparative Genomic Hybridization (CGH), and then applying a new ultra-rapid (600 times faster) freezing method called vitrification to preserve these chromosomally normal eggs safely and indefinitely in a state of suspended animation.

The process of combining CGH testing with selective egg vitrification, and the banking of only chromosomally normal eggs has several potential applications, the most obvious of which are:

• Fertility Preservation, for women who want to defer childbearing till later

• Fertility Rescue, for women who want to store and preserve their eggs pr before undergoing fertility-threatening cancer treatment

• Donor Egg Banking, where selected viable eggs would be stored and subsequently made commercially available for IVF and embryo transfer to women for whom egg donor-IVF provides the only means by which they can go from infertility to family.

Rather than waiting, often on a long waiting list, to access a preferred fresh egg donor, patients worldwide would be able to choose one or more eggs from a web-based catalogue. The web-based catalogue would give detailed information on the background of the egg donor(s) that produced the eggs the patient is potentially interested in purchasing. Upon purchase, the frozen eggs would be shipped to the patient’s Physician. The entire process from beginning to end should not take longer than 4-6 weeks to complete.

So, what advantages would a CGH- Donor Egg Banks have over the banking of non-genetically tested eggs?

1. Each CGH-normal egg, upon being thawed is about 7 times more likely to result in a live birth.

2. Given this improved viability, pregnancies resulting from such embryos are 3-4 times less likely to miscarry than embryos derived from non-CGH tested eggs.

3. Because the baby rate per CGH-normal embryo transferred is about 60% (more than 80% of embryos derived from CGH-normal eggs would likely also be chromosomally normal), there is no need to ever transfer more than 2 such embryos at one time. As a result, the risk of triplets or greater is negligible.

4. Given that such embryos are derived from eggs that have been chromosomally tested as normal, there would be a minimal risk of chromosomal birth defects such as Down's syndrome.

The cost in the United States of donor egg IVF is the highest in the world (all told, about $25,000-$30,000 per cycle). As a consequence, many women/ couples currently travel abroad for lower cost treatment. In fact, such “medical tourism” is fast becoming a significant industry in. European countries such as Spain and the Czech Republic, India, South Africa and Australia.

In the United States, much of the cost of donor egg IVF relates to the amount paid as donor stipends. As currently conducted, IVF using donor eggs is both complex and cumbersome. It requires donor selection which is often a tedious process that takes months to complete, independent consultation and medical evaluations of both the recipient and the egg donor, thorough microbiologic and genetic testing of all parties involved, followed by synchronization of the recipient's menstrual cycle with that of the chosen egg donor. Thereupon, the donor is stimulated with fertility drugs and monitored. At precisely the right time, the donor receives a trigger shot with human chorionic gonadotropin (hCG) and the recipient's hormone treatment regime is altered to coincide. About 36 hours later, the recipient’s eggs are harvested under anesthesia and fertilized with designated sperm. The embryos are cultured and when, 3 to 5 days later they reach a certain stage of development, are transferred to the recipient's uterus.

By allowing patients to procure one or more banked CGH-normal eggs (derived from fully pre-tested donors) for fertilization and subsequent transfer of the resulting embryo(s) to a hormonally prepared uterus markedly improves efficiency without compromising success rates.

A few IVF programs and egg donor agencies already offer their clients access to Donor Egg Bank services. However, the dismal reported average baby rate per non-CGH tested frozen egg (i.e. <4%) means that a recipient would need to purchase numerous eggs to have a realistic chance of a successful pregnancy. By offering patients fully karyotyped, CGH-normal banked eggs; they would not need to purchase more than 1or 2 eggs for about $3,000 per egg at a time. Since each CGH-normal egg would likely yield about a 27%-28% baby rate (i.e. a 7 to 8-fold improvement over other options), the birth rate following the transfer of 2 resulting embryos would be about 65%. This success rate is as high as any comparable reported results with conventional IVF-egg donation and it would come at 1/2-1/3 the current cost for such services in the United States.