LONDON, England (CNN) -- Some IVF clinics came under fire this week for marketing egg-freezing services to young women who may want to postpone motherhood until they are ready.
Should women over 30 give freezing eggs the cold shoulder?
The procedure requires a course of drugs to stimulate the ovaries followed by a surgical operation to extract the eggs, which are then frozen until the woman wishes to use them.
At least three British clinics have announced egg freezing programs for women who wish to delay motherhood. But the American Society for Reproductive Medicine has said that the procedure should not be used for "social" reasons and instead limited to women who are undergoing cancer treatment, those experiencing early menopause or women with ethical objections to freezing embryos.
But proponents of the technique say it is "empowering" to women -- many of whom face social rather than biological barriers to having a child. These barriers include commitment phobic partners, not meeting the right partner until later in life or both partners needing to work full-time to afford a mortgage.
But critics including some IVF specialists say this insurance policy is nothing short of false hope, with the success rates of freezing eggs too patchy.
"Women may feel that by having frozen their eggs, they have ensured their future fertility, but existing medical evidence doesn't justify that conclusion," said Marc Fritz, chairman of the society's practice committee. "The sole purpose of this advice is to prevent women from being exploited."
What is frozen egg technique?
With age, women's eggs accumulate genetic damage which causes fertility to fall rapidly after 35. Older eggs result in poorer quality embryos which are more likely to be miscarried. By 40, the average miscarriage rate reaches 40 per cent. Some experts believe that by using a woman's younger eggs in the process she is able by-pass many of the problems women with older eggs face.
During the egg-collecting procedure, doctors typically retrieve 10 to 12 eggs, to be replanted in the woman's womb and fertilized when the woman is ready to have a baby. But some of the eggs will not survive the freezing, storage and thawing process. At best, the chance of a woman having a live birth from a single thawed out egg is just 2 per cent, according to U.S. experts. They say the costly procedure should be saved for those with fertility problems.
Does it work?
UK specialist Dr Gillian Lockwood told a U.S. conference that success rates could be as high as 30 percent, and it was wrong to deny women the option. According to a story in The Guardian, "Figures from the Human Fertilization and Embryology Authority show 3,602 eggs have been frozen in UK fertility clinics since 1999. Of those, 483 have been thawed to use in fertility treatment, but only four babies have been born as a result.
"Approximately 200 British women have opted to have their eggs frozen, with each storing on average around 20 eggs. According to those figures, each woman has at best a 40 percent chance of having a live birth if all the eggs survive storage and thawing and are able to form healthy embryos."
As the treatment is in its infancy, some experts are worried that there may be harmful effects on children born from frozen eggs.
The ASRM practice committee said that, as only a few hundred babies had been born worldwide from frozen eggs, it was too early to say that the procedure was safe for the children that it created. Andrea Borini, of the Center for Reproductive Health in Bologna, looked at 123 babies, and found only two with major abnormalities -- less than 1 per cent, comparable with conventional IVF.
Ilan Tur-Kaspa, of the University of Chicago, found five major abnormalities among nearly 550 babies. Dr Borini backed the ASRM advice and said that data from 100,000 births would be needed to confirm safety.
Dr Tur-Kaspa said it was already clear that egg-freezing was safer than other mainstream medical procedures.
The process costs around around $6000 plus storage costs. E-mail to a friend