Fertility in Reserve
After years of technical obstacles, scientists have found ways to freeze
eggs for later use, helping women whose ability to have babies is threatened
by disease or aging.
By SHARI ROAN, Times Staff Writer
The bad news piled up on Shannon Lee faster than she could absorb it. At
31, she had been diagnosed with breast cancer. Not only would she need a
double mastectomy, the subsequent radiation and chemotherapy could leave her
sterile, ending her dream of having a baby.
But Lee's doctor also gave her hope. Confident that she would beat the
cancer, he urged her to undergo an experimental procedure in which some of
her eggs would be removed prior to chemotherapy, then stored for
fertilization at a later date, thereby preserving the possibility that she
could have a child. Heartened, Lee had 12 eggs extracted and frozen at an
"It's something I had to do," the Buena Park woman said. "I may not need the
eggs, but it's nice to know they're there."
Although the technology is in its early stages, egg freezing--called egg
cryopreservation--is now an option for women like Lee who face an imminent
loss of fertility. And soon, experts say, the procedure should become a
popular alternative for an even larger pool of women, those who risk losing
their eggs to normal aging before getting the chance to have a baby.
"There is growing optimism about egg freezing," says Dr. Patrick Blohm, a
Jacksonville, Fla., doctor who is among the most successful U.S. researchers
pursuing egg freezing. "We're still not there yet, but we're getting close.
There is momentum behind it now."
At least a half-dozen reproductive health clinics nationwide have established
egg freezing programs, some of them as part of research projects. Many other
clinics perform egg freezing on a limited basis, such as for young cancer
"These people have nothing to lose," Blohm says of women whose fertility is
threatened by illness. "We still have not opened up egg freezing to the
masses, but we're not too far away from doing that. We are encouraged that
some major hurdles have been overcome."
A handful of infertility clinics nationwide are already touting the service
as an exciting new option for any woman who wants it. But that kind of
marketing, as well as highly publicized announcements of a few births after
egg freezing, has been criticized by some doctors as premature. Published
reports put the number of births worldwide after egg freezing at 30, but some
doctors say recent progress has pushed that number closer to 100.
"I think many of us are taking a wait-and-see attitude," says Dr. Richard
Paulson, an infertility specialist at USC who does not offer egg freezing.
"It's an unproven technology, and the success is hit or miss as compared to
embryo cryopreservation, which has an established track record and for which
national statistics are available."
But Dr. William Keye Jr., president of the American Society of Reproductive
Medicine, says perfecting the ability to freeze unfertilized eggs will be a
major milestone in reproductive health care.
"This will be the last group for whom we don't have good answers," Keye said.
"I think we will finally have something to offer them."
The Ability to Put Fertility on Hold
Infertility doctors largely agree that egg freezing could have vast medical
and social implications.
Men have long been able to freeze sperm, but preserving oocytes--eggs--has
proved to be a far different, and difficult, task. Girls are born with 40,000
to 200,000 eggs, a supply that begins to dwindle when menstruation begins.
Medicines to treat cancer, rheumatoid arthritis and some other diseases can
destroy eggs. And an estimated 3% of women have a genetic disorder called
premature ovarian failure, in which the ovaries shut down 10 to 20 years
before what is considered normal.
Often, women who are about to lose their fertility undergo in vitro
fertilization, in which eggs are removed from the ovaries and fertilized and
the resulting embryos frozen. But many single women do not have that option
unless they agree to use sperm from an anonymous donor or an acquaintance,
and others do not want to create embryos that may not be used.
Besides providing hope to these women, routine egg freezing has significant
practical benefits. Women who wish to postpone childbearing because of career
demands could bank their eggs in their 20s or early 30s, when the eggs are
healthier, for later use. Recent research has found that egg quality begins
to decline in the mid-30s.
"There is massive interest among women who are around 38 and haven't found
their life partner and who want to lay down a few eggs for later in life,"
says Michael Tucker, an Atlanta embryologist who made headlines in 1997 when
he announced the birth of twins after freezing eggs and fertilizing them with
a needle via intracytoplasmic sperm injection. That development was
considered a critical advance, and Tucker says the announcement spurred
thousands of inquiries from single women.
Karen, an unmarried businesswoman who asked to remain unidentified, had eggs
frozen at a Southern California infertility clinic last year.
"I've been so busy with my career," she says. "Relationships have been there,
but none where I wanted to have a baby with someone. But family is very
important to me, and all of a sudden I'm 37 years old. I thought I had better
stop time right now."
Egg freezing also could eventually curb the use of donor eggs, often required
by older women who wish to become pregnant. For couples who will still
require donor eggs (if egg quality is poor, for example), cryopreservation
could reduce its expense and inconvenience. Couples often pay about $20,000
for a single donor's fresh eggs, but those costs could be reduced by as much
as two-thirds if the eggs could be frozen and divvied up among several
couples, says Tucker.
And routine egg cryopreservation could help resolve the growing dilemma of
what to do with tens of thousands of unwanted frozen embryos stored in
infertility clinics worldwide. Some people consider embryos human life and
feel it's morally wrong to discard them.
Lee, for example, was in a serious relationship when diagnosed with cancer
and could have had her eggs fertilized and frozen as embryos. But both she
and her boyfriend (they later married) were uncomfortable with that option.
"My husband didn't like it that we were basically creating a child and then
would be killing it if we didn't use it. An egg isn't a life yet," says Lee.
Lee, who completed cancer treatments a few months ago, still hopes the cancer
therapy did not destroy her fertility and that she and her husband, Todd, can
have a baby the natural way. But, she says, she was willing to hedge her bet
despite the $9,000 cost of egg freezing.
Proper Thawing Is Critical to Egg Survival
The growing enthusiasm for egg freezing rests largely on recent progress in
thawing eggs. In the past year, several researchers have reported that 60% to
80% of eggs survive the critical thawing process. That is comparable to the
survival rate of thawed embryos, says Blohm, who has produced several births
from frozen eggs. Prior to 1994, only 10% to 20% of eggs survived thawing.
Unlike sperm, the egg is a large, fluid-filled cell that can become riddled
with damaging ice crystals when frozen. Now, however, researchers are
experimenting with a flash-freezing process, called vitrification, that
prevents ice crystal formation.
Other researchers are injecting sugar solutions into eggs before freezing to
better preserve them. A recent report in the journal Fertility and Sterility
showed that, in a study of 158 eggs, 63% of eggs with a sugar solution
survived freezing and subsequent thawing, compared with only 13% in a control
Doctors have also been able to dramatically improve the fertilization rate of
thawed eggs by using intracytoplasmic sperm injection, Tucker says. The outer
shell of the egg, the zona, often becomes impenetrable after freezing, but
the procedure bypasses that problem because the sperm is injected into the
egg using a needle.
"We've always known what the limitations of egg freezing were, but we've now
learned a lot more about how to circumvent the problems," says Tucker.
Thawing and fertilizing frozen eggs is just half the battle, however. Much
less is known about the success of implanting the ensuing embryos in the
uterus and producing a baby. Only a portion of thawed, fertilized eggs become
viable embryos, says David Hill of the ART Reproductive Center in Beverly
"It's a numbers game," Hill says. "The more eggs you have to start with, the
more likely you'll have a normal, healthy, cleaving embryo by the time it's
Patients Should Note Procedure Is Still New
Women interested in egg freezing should be aware of its unproven track
record, experts caution.
People considering egg freezing should ask the doctor about his or her
thawing and fertilization success rates and if he or she has produced any
"It does appear that there are some sites that do it better than other
sites," says Susan Lazendorf, an infertility specialist at the Jones
Institute for Reproductive Medicine in Norfolk, Va. "It should be made clear
to a patient that there are no real known success rates. And the best bet is,
if you have a partner identified, to go ahead and make embryos."
While predicting that egg freezing will become as useful as embryo freezing
"in the very near future," Blohm says the procedure should still be
considered experimental until data can show that birth defects are not higher
among children born from frozen eggs.
"We have to have data that supports the safety of the process before we open
it up to wider use," he says.
In contrast, cancer patients should be alerted to the option despite the
unknowns, says Dr. Beth Ary of the Reproductive Specialty Center in Newport
"We have protocols involving males [with cancer] where they are informed that
they can store sperm," says Ary, who later this month will freeze the eggs of
a woman with colon cancer. "Most of these [female] cancer patients would like
to have known about egg cryopreservation and IVF. Our big issue now is
educating cancer doctors about this."
There is less agreement among infertility specialists on whether egg
freezing--as the technology stands now--should be encouraged among single
women who wish to store eggs as a way of putting fertility on hold. Egg
extraction is a low-risk procedure, although it does involve minor surgery
and temporary use of strong medications. And it is expensive.
Dr. David Diaz, of West Coast Fertility Centers in Fountain Valley, is one of
the few doctors who now urge single women to consider egg banking if they are
concerned about advancing age. A woman can have a blood test to determine if
her ovaries are losing function.
"Age is very much a factor in what we do," Diaz says. "Women often come in at
40 and want to freeze their eggs, but we really need to see them much
Increasingly, infertility doctors may accept these women for egg freezing
because the science is advancing and the demand is high, says Lazendorf.
"I think a lot of patients are storing their eggs now and are hoping for
improvements in technology so they can use them," she says. "They are waiting
for the technology to catch up."