Frozen eggs give women future birth options

By MARTIN JOHNSTON

Women worried about childbirth interfering with their careers have been given a new option for storing their fertility in the freezer.

A fertility group has begun freezing women's eggs, after gaining ethical approval from a Government committee.

The procedure would also allow women to reduce the risk of having a baby with Down syndrome because the risk is higher in eggs produced by older women. But the procedure does not come cheap.

Fertility Associates charges around $7000 for obtaining and freezing the eggs, plus $150 a year for storage. There is no state funding.

Trying to get pregnant with the thawed eggs would be by IVF (in-vitro fertilisation), costing the woman about $1000 more, unless she qualifies for public funding.

Dr Mary Birdsall, of the group's Auckland clinic, said yesterday that four women's eggs had been frozen, but none had yet had them fertilised.

"We've only been given permission a couple of months ago."

The National Ethics Committee on Assisted Human Reproduction permitted freezing eggs for both lifestyle and medical reasons. The approval also covers couples who have religious objections to freezing embryos and when sperm cannot be obtained following egg collection.

Women's fertility can be threatened by radiotherapy, endometriosis surgery and some types of drugs.

The four women are aged in their mid-30s and sought treatment for a variety of reasons.

A Fertility Associates director, Dr Richard Fisher, predicted lifestyle would be seen as the main reason.

"Everybody says what we are going to get is a whole lot of 25-year-old lawyers rushing along and saying, 'Freeze my eggs because I want to be a law-firm partner by the time I'm 35 and if I don't get pregnant then, I want to have a chance'.

"I haven't noticed a rush and we don't expect to see one."

While human sperm has been frozen for around 50 years, and the first frozen embryo baby was born in 1983, successfully freezing and thawing eggs has proved harder.

"Part of that relates to the egg being the biggest cell in the human body," said Dr Birdsall. "And it has been difficult to prevent ice crystals getting into the inside of the egg [where they] disrupt the inner-cell workings."

Fertility Associates' clinical pregnancy rate with IVF had risen to 50 per cent in the past six months.

She did not know what the rate would be using thawed eggs, but the British Government's fertility authority says: "Most experts think that the live birth-rate using frozen eggs is likely to be very low."

Dr Birdsall said only 65 babies had been born worldwide so far from frozen eggs. A Spanish study found 16 eggs were needed to make a baby.

Studies on the health of the children born following egg freezing "have been reassuring thus far".

Otago University professor of medical ethics, Grant Gillett, said freezing eggs presented the question of the "granny mum scenario" and whether a maximum age should be set for fertility treatment. Ethicists disagreed on the answer.

How delayed parenthood works

The woman is given hormone injections for several weeks to stimulate egg production. Eggs, usually five to 15, are removed from the ovaries by a needle. This is done under sedation and with a local anaesthetic.

The eggs are put into a narrow tube and frozen in liquid nitrogen to minus 196C. They can be stored indefinitely. To be fertilised, eggs are thawed and sperm injected into them.

The fertilised eggs are grown into embryos and put into the woman's uterus.