The use of frozen donor eggs to assist with in vitro fertilization is on the rise, and it could be headed toward a tipping point in terms of public awareness and acceptance.
Advances in an egg freezing method known as vitrification have shown encouraging results in terms of live births, rivaling the results seen with fresh egg donation cycles. Add to that the significantly lower cost of in vitro fertilization (IVF) using frozen eggs and the increasing acceptance in the medical community, and it’s a recipe for growth in frozen donor egg banking.
"There’s been very rapid and very wide acceptance of this," said Dr. Daniel B. Shapiro, the medical director of My Egg Bank North America, a multicenter network of egg banks with locations throughout the United States including Atlanta, Boston*, Orlando, and Seattle.
Zsolt Peter Nagy, Ph.D.
The technology to freeze eggs has been around for decades, with the first baby born as a result of a cryopreserved oocyte reported in 1986. But the process was inefficient then and between 100 and 150 eggs might be needed to get a single pregnancy, according to Zsolt Peter Nagy, Ph.D., the scientific director for Reproductive Biology Associates, which is a partner in My Egg Bank.
"That was the level of efficiency for about 20 years," said Dr. Nagy said.
But the landscape started to change when scientists began experimenting with improvements to the egg freezing technique. A breakthrough came around 2006 with the use of a new process called vitrification. Although there are various methods of vitrification, it generally involves using a cryo-protectant and rapid cooling to solidify the cell without forming ice crystals. Many of the vitrification methods call for directly exposing the oocytes to liquid nitrogen.
In a randomized controlled trial of 600 recipients, which compared vitrified to fresh oocytes, researchers found no significant differences in fertilization, implantation, or pregnancy rates. Pregnancy rates per transfer were 55.4% for vitrified eggs, compared to 55.6% for fresh eggs (Hum. Reprod. 2010;25:2239-46).
It’s these types of results that are fueling the interest in frozen donor egg banking, said Heidi Hayes, CEO of Donor Egg Bank USA, a Rockville, Md.–based bank that opened for recipient use in March 2012.
"That is what changed it. Now it can be done successfully," Ms. Hayes said. "It’s going to change the field as a whole because of the new technology."
The field got another boost when the American Society for Reproductive Medicine (ASRM) issued a new guideline saying that the cryopreservation of mature oocytes – using both vitrification and slow-freeze protocols – was no longer experimental.
Removing the experimental designation means that practices wishing to use frozen eggs in IVF cycles won’t have to counsel patients that the procedure is experimental. It also means that an Institutional Review Board (IRB) won’t have to be involved in the informed consent process. That’s a significant change because a lot of practices don’t have access to an IRB, said Dr. Samantha M. Pfeifer, chair of the Practice Committee of the ASRM, which wrote the guidelines.
But ASRM is not endorsing frozen egg banking. Although the guidelines state that much of the best data supporting the use of oocyte cryopreservation was in the setting of donor oocyte cycles, the group said it would need more clinic-specific data on the safety and efficiency in the donor population before it could recommend universal donor banking. The ASRM statement does recommend oocyte cryopreservation for cancer patients who are at high risk for infertility because of chemotherapy.
There are a lot of advantages to moving toward frozen eggs, Dr. Pfeifer said, such as the ability to quarantine eggs to check for communicable diseases. But there are also lingering questions about how to use frozen eggs, she said. For instance, how long can these eggs be frozen and still be viable?
The other concern with moving rapidly toward universal donor banking with frozen eggs is that not every practice has the capability to freeze eggs. "There was some concern that if there was a sudden mandate from the government that everyone [would have] to use frozen eggs; we’re not equipped to do that yet," said Dr. Pfeifer of the department of obstetrics and gynecology at the University of Pennsylvania, Philadelphia. "A lot of things have to happen before that can become a standard procedure in this country."
The first step is removing the experimental label, she said. "Now that it’s not experimental, the reality is that people will be using this technique."
Even without a full-scale endorsement from the ASRM, momentum for frozen donor egg banking has been picking up. The cost is a big part of that, Dr. Shapiro said.