Cryopreservation: a new miracle?
Women who want to delay their pregnancies can now freeze their eggs effectively and safely. But success is not guaranteed.
- In Europe, the average age for a first pregnancy is 29, and 3.2% of first births are to mothers over 40.
- Unlike America, Europe still frowns on egg-freezing for non-medical reasons.
It is well established that a woman’s fertility declines after age 35, as her egg count and egg quality wane. At the same time, European women are waiting longer and longer to have their first child. The latest Eurostat reports show that the average age for a first pregnancy is 29, and 3.2% of first births are to mothers over 40. Society is changing, but biology has yet to catch up.
Egg freezing, or cryopreservation, is one solution. The procedure involves ovarian stimulation for 10 to 12 days, after which the eggs are extracted under general anaesthesia and frozen. Then, when the patient wants to get pregnant, the eggs are thawed and fertilised in vitro.
Technical advances now make it possible to freeze eggs more effectively and safely. The turning point came with vitrification, a method for “flash freezing” eggs developed in the late 1990s. Its key advantage is to prevent the formation of ice crystals. Considered experimental until the beginning of the 2010s, the technique is now recognized as superior to other methods. “The egg survival rate now ranges between 85% and 95%, compared with 40% to 60% using the previous slow-freezing techniques,” says Laura Rienzi, senior clinical embryologist for the Genera Centres for Reproductive Medicine in Rome.
In the US, specialised clinics are cropping up from Manhattan to Silicon Valley, while women sip champagne and nibble canapés at swanky egg-freezing parties. Tech giants Facebook and Apple caused a stir when they announced that they would start covering egg-freezing costs for their female employees.
Not a trend in Europe
So-called “social” egg freezing has been slower to catch on in Europe. Most cryopreservation procedures are performed for medical reasons, for example before a treatment, like chemotherapy, that could impact fertility. The latest statistics from the European Society of Human Reproduction and Embryology report 9,126 egg-freezing cycles in 16 countries during 2013, of which only 13.1% were for non-medical reasons. In 2017, Genera centres in Italy performed fewer than 100 cryopreservation procedures, nearly all of which were for medical reasons.
“Lots of women and couples would like to postpone having a child,” says Rienzi. “But freezing their eggs is no guarantee. For eggs extracted before age 35 under the best conditions (more than 14 high-quality eggs), the chances of getting pregnant are 80%, not 100%.” In addition, most women who come to the centres are often already 38 to 40, dramatically reducing the success rate. “We have to be very transparent, especially because it is quite a gruelling medical process, especially from a psychological point of view.” And that does not factor in the high cost, with prices for one or more vitrification cycles generally ranging from €2,000 to €5,000, depending on the country and added services.
Clearly, egg freezing is not the miracle solution that it is sometimes made out to be. Rienzi believes that the procedure should be presented as one of many options. “Facebook and Google were attacked from all sides,” she notes. “But everyone forgot to mention that they also offer generous maternity and paternity leave and provide genuine support for parents, especially child care.”
Autonomy vs. dignity
From an ethical standpoint, social egg freezing raises few issues, says Valérie Depadt, lecturer in private law at University of Paris 13. “No major ethical principle prevents a woman from preserving her own eggs,” she says. “I see the main drawback as the hope it can bring. We have to be very clear that we’re talking about another opportunity and not a guarantee.”
As for the risk of commercialisation, Depadt is not worried. “We’re far from all that,” she says. “What’s happening in the US is unlikely to be exported to Europe. In America, biomedicine is based on the principle of autonomy. In Europe, the principle of dignity is more important.” Only a handful of European countries still ban social freezing, but France is one of them.
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