Egg Freezing as Viable as 'Fresh' Eggs, Fertility Experts Say10/19/12
FRIDAY, Oct. 19 (HealthDay News) -- A leading group of U.S.
fertility doctors says there is now enough evidence to support the
freezing of a woman's eggs as a way to preserve fertility in young
Studies conducted over the past few years show that
fertilization of frozen eggs has roughly the same success rate in
terms of pregnancies and live births as in vitro fertilization
using fresh eggs.
"We came to the conclusion that we really could not call this procedure experimental anymore, and we decided to lift that designation," Dr. Samantha Pfeifer, chairwoman of the American Society for Reproductive Medicine (ASRM) practice committee, said at a news conference Wednesday. "As of the publication of this document, oocyte cryopreservation is no longer considered experimental, which is a huge advance compared to previous documents."
The ASRM's last statement on the matter, issued in 2008, deemed
the practice still experimental. The new statement is published
Oct. 22 in the journal
Fertility and Sterility.
Researchers found almost 1,000 published papers on the topic of
egg freezing -- called oocyte cryopreservation -- and selected the
most relevant for analysis. They concluded that survival rates of
the eggs, implantation rates and pregnancy rates are similar to
those when using fresh eggs.
Much of this is due to the use of a new freezing technique
called oocyte vitrification.
Because eggs contain a lot of water, slow-freezing ran the risk
of producing ice crystals, which would damage the egg. Oocyte
vitrification is essentially a flash-freezing technique, done after
water has been extracted from the egg, which circumvents the
problem of ice formations.
There does not appear to be any higher rate of birth defects
among the 1,000 children born using this technique when compared to
children born using fresh eggs or those born in the general
population, according to the report.
Long-term data is limited, however, cautioned Dr. Eric Widra,
chairman of the Society for Assisted Reproductive Technology
"This is still a young technology," he said. "The number of children born using this method is still small."
By contrast, more than a million children have been born from in
vitro fertilization using fresh eggs, he said.
The age of the woman at the time of treatment is paramount when
predicting outcomes, Widra added. Few studies have looked at women
beyond the age of 35 or 40, and younger women clearly have better
There just isn't enough evidence supporting oocyte
cryopreservation as an "elective" treatment for women who want to
defer starting a family until later in life, Widra said.
The ASRM document said the technique could be used in couples
that were looking at imminent infertility perhaps as a result of a
medical issue, such as chemotherapy for cancer, or among couples
undergoing in vitro fertilization that were having trouble
collecting sufficient sperm.
"Eggs could be frozen at that point to allow future collection of sperm for fertilization," Pfeifer said.
The procedure does carry some risks, such as the possibility of
injury while eggs are being retrieved, and it is unclear if
insurance would cover the cost of the procedure for certain groups
of women, Pfeifer added.
The American Society of Reproductive Medicine has more on
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