Eggs on ice

Women can hope to beat the biological clock by freeze-storing their eggs and using them later

Written by Newsweek

September 2, 2006 12:00 AM IST

3 min read

The danger of delaying childbearing, of course, is that a woman who eventually wants a baby may be unable to have one because her eggs are no longer viable. But researchers have developed a procedure that, while not stopping a woman8217;s biological clock, can in effect act as a snooze button. Egg freezing, or 8220;oocyte cryopreservation,8221; uses hormones to boost a woman8217;s production of eggs, which are then extracted and frozen, allowing them to be thawed, fertilised and implanted in her womb at a later date. Freezing puts the eggs in a state of suspended animation, meaning that in theory, a woman can keep a viable store of eggs on ice long after her body8217;s natural supply is depleted.

While egg freezing is available primarily to cancer patients facing infertility from chemotherapy and radiation, clinics are offering the procedure to otherwise healthy women who simply want to postpone childbearing for personal reasons. Italy, which has laws banning the use of frozen embryos, has been a leader in developing one technique, where extracted eggs are dipped into a solution and then slow-frozen. South Korea has advanced another method, called vitrification, where liquid nitrogen is used to flash-freeze the eggs. Dr Bradford Kolb of the Huntington Reproductive Center in Pasadena, California, has been providing egg freezing to the general public since 2004. 8220;It8217;s no guarantee for future pregnancy, but we8217;re giving women the potential to have children with their own eggs,8221; he says.

The first pregnancies from frozen eggs were reported almost two decades ago, but even today only about 200 babies have been born from them. Some experts worry that the practice is being widely adopted before enough is known about success rates. By contrast, about 150,000 children have been born from frozen embryos over the same 20-year period. Dr Kutluk Oktay, of Cornell University8217;s Center for Reproductive Medicine and Fertility, recently analysed eight years8217; worth of data and found that the live-birth rate per thawed egg was only 1.9 percent using the slow-freezing technique and 2 percent with the vitrification method.

The American Society for Reproductive Medicine endorses the procedure for cancer patients but not for healthy women, saying the technology is not advanced enough to be offered on an on-demand basis. 8220;It8217;s still not terribly effective,8221; says ASRM8217;s Eleanor Nicolls. 8220;The frozen eggs do not survive very well, they don8217;t fertilise as well, and the chances of a pregnancy are much lower than with fresh eggs.8221; Skeptics and proponents agree if a woman wants to freeze her eggs, the best time to do so is in her late 20s to early 30s, before their viability starts to decline.

Though the industry does not track the numbers using the freezing technology, more women are clearly exploring it. Christy Jones, CEO of Boston-based Extend Fertility, says her company has frozen the eggs of more than 200 women who are hoping to beat the biological clock. 8220;What we8217;re hearing from women is that it takes the pressure off of feeling like they have to find Mr Right immediately,8221; says Jones. 8220;It8217;s something they can do to avoid the sense of desperation that time is running out.8221; Just like hitting the snooze button once again. DAREN BRISCOE

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