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Waiting for Mr Right? You can’t preserve eggs in Singapore yet
What is social egg freezing?
Social egg freezing is when a woman facing infertility due to social reasons, such as not having met Mr Right, freezes her eggs through an experimental technique for later use when she does meet him. Where is it available? It is offered by doctors in Malaysia, Australia, Britain, the Netherlands, the United States and Canada. It is currently not allowed in Singapore.
 Where are eggs produced?
They are produced in a woman’s ovaries (see diagram). Usually, one egg is produced and released every month.
How does a woman tell how many eggs she has left?
A blood test can be done to measure a woman’s level of Inhibin B, a fertility hormone produced by the ovaries. The higher the level, the more eggs she has left.
How are eggs harvested for freezing?
The woman is given in-vitro fertilisation (IVF) drugs for around 14 days. The drugs stimulate the ovaries to generate a number of mature follicles (the fluid-filled sacs containing eggs). This is the first step of IVF, in which a woman’s eggs are harvested and fertilised by sperm outside the body and the resulting embryos are placed in the womb. Shortly before the doctor calculates that the eggs will be released through the fallopian tubes during ovulation, the woman will be sedated. Using ultrasound as a guide, the doctor will pull eggs out of her ovaries with a hollow needle inserted through the wall of the vagina. The eggs, which are in fluid when they are extracted, are poured onto a flat dish. Individual eggs are identified with a microscope and withdrawn for freezing.
How are eggs frozen?
Eggs can be frozen by slow freezing or vitrification (ultra-rapid freezing). In the former, eggs are placed in a sugar solution containing anti-freeze and cooled slowly in a freezer. The whole process takes two hours, after which the frozen eggs are transferred to a storage tank containing liquid nitrogen at -196 deg C. In ultra-rapid freezing, the eggs are frozen within five minutes. It involves using a high-concentration anti-freeze solution with sucrose to draw some of the water out of the egg and freeze the egg so quickly that ice crystals do not have time to form. The move towards vitrification is a recent trend in IVF because it saves time, does not require expensive equipment and gives a higher survival rate, said Dr Yu Su Ling, senior consultant at the department of obstetrics and gynaecology and director of the Centre for Assisted Reproduction at Singapore General Hospital. How long can eggs be stored?
Technically, eggs can be frozen indefinitely.
How can the eggs be used?
When a woman decides the time is right for a baby, an egg is thawed slowly. This involves a carefully controlled drop in temperature before the heat is turned up. After being inseminated with sperm, the egg becomes an embryo and is inserted into the woman’s uterus. If this is successful, the woman becomes pregnant.
Is it easier for an older woman to get pregnant with younger eggs?
Doctors say that using frozen “young” eggs will give a better pregnancy rate compared to using fresh eggs from a 45-year-old woman.
What are the success rates?
Fertility experts disagree over the chances of a baby being born from a frozen egg. Some suggest there is up to a one in three chance of having a baby. Others claim success rates are as high as 50 per cent. Most experts agree that success depends on the woman’s age, the number of eggs removed from the ovary and how successfully the eggs are fertilised. All the babies born so far out of the freeze-thaw process have been healthy.
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