Italian births raise hopes for egg-freezing treatment

Thirteen children have been born to couples using frozen eggs in a development that could extend women's reproductive life, scientists reported yesterday.

Thirteen children have been born to couples using frozen eggs in a development that could extend women's reproductive life, scientists reported yesterday.

Italian researchers who froze 737 eggs from 68 couples say the high number of births gives them hope that a breakthrough in the treatment may be only a few years away.

Only 37 per cent of the eggs survived the freezing and thawing process but the researchers from Tecnobios Procreazione in Bologna say they hope to achieve a 75 to 85 per cent survival rate by altering the medium in which the egg is stored.

Egg freezing has been pursued by fertility experts for more than a decade because it would allow women to store eggs in their twenties and start a family in their forties.

It is more difficult than freezing embryos, because eggs are more vulnerable, but the first pregnancy from a frozen unfertilised egg was achieved in 1986. Doctors have struggled since to perfect the technique. Dr Giovanni Coticchio, who led the Italian study, said a 37 per cent survival rate for the eggs was not good enough.

But he added that the technique had the potential to revolutionise IVF treatment.

"Women could have much more control of fertility treatment. They could store their eggs at a younger age, which then means the chances of a successful pregnancy increase because the quality of the eggs reflects the mother's age. It also gives women the same opportunities as men who have their sperm frozen." To improve the success rate, the team is planning to increase the concentration of sucrose in the freezing medium to lower the water content and reduce the risk of ice forming. However, this makes the eggs susceptible to "dehydration stress" during thawing.

The treatment is normally offered only to women being treated for cancer who are at risk of losing their ovaries. Removing eggs for freezing is an invasive process that would not normally be contemplated by healthy women, given its low success rate.

But if it could be perfected it would open the possibility of women freezing eggs and holding them in storage until they meet a partner.

Simon Fishel, director of the Centres for Assisted Reproduction group of fertility clinics, said egg freezing posed technical problems and was costly, inefficient and uncomfortable for the patients.

"Freezing is still at the experimental stage so women have tended to use it only if they are undergoing medical treatment. But if the technique improves they may start to choose it for lifestyle reasons."

He added: "The Italian team are using well-known techniques by tweaking the sucrose concentration but the tweaking may lead to a breakthrough."

Mohammed Taranissi, director of the Assisted Reproduction and Gynaecology Cen- tre in London, said: "A lot of people have been looking at this. We need to perfect the technology but over time it could certainly become possible."

Developments in the technique could benefit research as well as fertility treatment, he said.