Next week after we celebrate Mother’s Day, I will report on the state of the world’s mothers from data that was just released by “Save the Children”. But this week, I thought I would be more uplifting and talk about the advances in freezing eggs which can allow women to become mothers when they otherwise could not.
One of the directors of a fertility clinic in Beverly Hills visited my office last week. He proudly told me about the 30 women that his clinic had helped conceive and reach full-term pregnancy with the use of egg freezing. I wanted to see the published peer reviewed articles on success rates and he sent me a 2013 article from the Journal, “Fertility and Sterility”. The report was developed by the practice committee of the American Society for Reproductive Medicine (ASRM) in collaboration with the Society for Assisted Reproductive Technology (SART).
A bit of history about the freezing and preserving of sperm, eggs and embryos…The first human birth from frozen sperm was reported in 1953. The first human birth from a frozen embryo was reported in 1984 and in 1986, the first human birth from frozen oocytes (the medically correct term for eggs) was reported. Freezing sperm has been a lot easier than trying to do so with oocytes. In the past, when a mature oocyte was frozen the chromosomes were damaged by intracellular ice formation during the freezing or thawing process. But in the last few years, there have been modifications and an alternative known as vitrification has been developed. This is a process of cryopreservation using high concentrations of a cryoprotectant and ultra rapid-cooling to solidify the cell into a glass-like state without the formation of ice. (I know this sounds lofty and complicated but think of it as flash freezing.) Vitrification has significantly improved survival of the cryopreserved mature oocytes and results in better pregnancy rates. But that rate is still dependent on the age of the woman from whom the oocyte is retrieved. An older egg is less likely to be fertilized and develop into an embryo no matter if it is fresh or frozen!
In small studies in the US in women under the age of 37, their frozen eggs had a survival rate of 89%, there was a successful fertilization rate of 78%, an implantation rate of 45%, and a live birth rate per transfer of 58%. Another study showed a live birth rate per transfer of 65% in women under the age of 35 who had previously undergone tubal ligation. But these were all younger women. If eggs were frozen from older women, the number of successful pregnancies significantly diminished. Moreover, when I asked how many eggs have to be retrieved in younger patients to allow for a good chance of a successful pregnancy, I was told that 20 should be harvested. This usually means two cycles of strong fertility drugs in order to get multiple oocytes to develop to the point where they can be harvested and then frozen. I then enquired how much a procedure with fertility medication and oocyte freezing would cost. The answer was “in the range of $24,000″.
The conclusion of the experts in the article was that there is good evidence that fertilization and pregnancy rates with frozen oocytes are similar to IVF with fresh oocytes in young infertility patients and oocyte donors. There have been no known increases in chromosomal abnormalities, birth defects, or developmental deficits in children born from cryopreserved oocytes. Therefore, they state the technique should no longer be considered experimental. And it is recommended for patients facing infertility due to chemotherapy or other therapies that would destroy their ovaries (after appropriate counseling). But they want more widespread clinic specific data on the safety and efficacy of oocyte freezing in donor populations.
It will definitely make it easier for women who need to use donor eggs if they can access previously donated and frozen eggs. In order to use fresh donated oocytes, the recipient and donor’s cycles have to be synced in the same facility. And if a woman has to use her own oocytes for IVF (especially when there is a low sperm count and IVF is used to insert sperm directly into the egg), once she freezes her oocytes she can do the procedure at a time and place that is convenient.
In the article, the committees do not yet recommend oocyte cryopreservation for the sole purpose of circumventing reproductive aging in healthy women. That doesn’t mean it’s not “catching on” especially here in Beverly Hills! Most women don’t even think about their diminished fertility until they are in their late 30s. But by then, freezing their eggs will have an expensively diminished return. I’m not sure what I should tell my daughter…