The freezing of cells and tissue while maintaining their viability is called cryopreservation.

The science of freezing has advanced significantly over the past decade allowing fertility centres like Sunfert to safely freeze sperm, eggs and embryos (fertilised eggs) for prolonged periods with minimal reduction in their survival upon thawing.


Egg, sperm and embryo banking is similar to financial banking, whereby the samples are banked at Sunfert laboratory. Sunfert employs a state-of-the-art method in freezing called “vitrification”. In the past, tissues are frozen using the “slow freeze” method where the tissue survival is only about 60% upon thawing due to formation of ice crystals in the cells. The vitrification method is essentially a quick-freeze method whereby the eggs and embryos become glass-like in an instant. Upon thawing at a later date, the eggs and embryos survive virtually intact.

Patients who are going to undergo cancer treatment may choose to freeze their sperms or eggs first prior to treatment as cancer treatment may invariably render them subfertile. Studies have shown that they face cancer treatment better knowing that they may still be able to have children later.

There is a growing trend for women to marry later and delay childbearing, often to pursue education and career or sometimes due to lack of suitable partners.

Given that fertility declines with age, egg freezing offers an option for women to preserve their fertility without the pressures of their biological clock. Women can now choose to freeze their healthy unfertilised eggs until a time in the future when they can or are ready to begin a family.


In the egg freezing programme, the woman undergoes a series of injections similar to the standard IVF programme (refer Assisted Conception). The best age for egg freezing is early 30s or younger, certainly before the age of 40 if possible. The eggs are harvested and subsequently frozen using vitrification method and stored in liquid nitrogen (-196 ͦ Celcius). Some women may choose to have more than one cycle of freezing to ensure there are enough eggs to be frozen for use at a later stage.

There are more studies emerging to show the efficiency of vitrifying eggs. Most eggs can now be utilised after thawing and roughly a third of women undergoing treatment conceive.

Like all new techniques, there are always fears of long term abnormalities in the resulting offspring. Any studies looking at these concerns must look at the risks ABOVE the background population risk. Whether the risk is worth it or not is a very individual decision. Certainly, the alternative of getting pregnant at an older age is not only difficult but also carries a higher risk of a baby born with problems like Down Syndrome.

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