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FERTILITY BREAKTHROUGH
Prospective mums can have their eggs frozen before treatment for use later on.
A NEW fertility treatment offered by some doctors here could give women about to undergo cancer treatment higher hopes of becoming mothers one day. As treatments like radiotherapy and chemotherapy can make a woman barren, she can now opt to have her eggs frozen ahead of these treatments for use down the road.
Freezing eggs is the easy part. Thawing tends to damage them, making them not fertilisable. When eggs are thawed, ice crystals tend to rupture the cells.
Doctors have thus re-looked traditional methods of freezing eggs and come up with flash-freezing. Also called vitrification, this form of cryopreservation super-cools the egg so fast that the transformation from liquid to solid is instantaneous.
Thawing does not damage it.
Professor Ng Soon-Chye of the O&G Partners Fertility Centre at Gleneagles Hospital said that nearly all eggs frozen at rapid rates survive thawing, compared to seven in 10 eggs frozen the conventional slow way.
Worldwide, only 200 to 300 babies have been born from eggs that were frozen this way. Singapore had its first baby from such an egg in June at Gleneagles Hospital.
The woman, who declined to be interviewed, is not a cancer patient, but was undergoing in-vitro fertilisation (IVF) to conceive.
As is usual for IVF, more than enough eggs were produced. Some were mixed with her husband's sperm to form embryos and implanted in her womb. The unfertilised eggs that were left over were flash-frozen. When the implanted embryos failed to "take", the woman took a break from trying for a baby.
A year later, her doctor L. C. Foong thawed her frozen eggs and combined them with her husband's frozen sperm. The couple had their baby.
Pregnancy rates for rapidly frozen eggs are almost the same as using fresh eggs - at 30 per cent, said Prof Ng. Singapore General Hospital (SGH) and KK Women's and Children's Hospital (KKH) have also started using this rapid-freezing method for their cancer patients' eggs; between them, they have used it on five patients so far.
Before this option became available, women about to start chemotherapy just had to hope for the best with the conventional methods of freezing the eggs, said Dr Yong Tze Tein, an obstetrician and gynaecologist at SGH.
Dr Loh Seong Feei, the head and senior consultant of the reproductive medicine unit in KKH, stressed that whenever possible, women who want babies should improve their odds by trying to get embryos implanted first rather than just go with egg freezing by either the old or new method.
This is because egg freezing is still relatively new, and these eggs still have to be put through fertilisation down the road.
Dr Loh noted that, apart from cancer patients, another group that could benefit from quick-freezing of eggs are Catholics, who do not want embryos - which they see as human life - discarded because of their religious beliefs.
Instead of freezing the additional embryos which may later have to be discarded, Catholics now have the option of just freezing eggs for later use.
Ministry of Health regulations only allow up to three embryos to be transferred to the mother's womb. But if IVF treatments yield more eggs than needed, the extras can be frozen for use later.
Career-minded women the world over are opting to freeze the eggs they produce in their prime and coming back for IVF treatments only when they are ready to start a family. This effectively stops their "biological clock" because when frozen, eggs stay at the age they were at when they were extracted.
In Singapore, however, MOH guidelines allow women to freeze eggs only for medical reasons and for up to five years.
Also, these women must be married and must apply for permission to keep the eggs frozen beyond five years.
Dr Yong said: "Freezing of eggs could be how we go in the future...From a social point of view, it sounds very attractive to many women who do not want to be bogged down by motherhood in their youth." But the ethical considerations still need to be first overcome, she warned.
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