Egg freezing is becoming increasingly popular. Here's what you need to know about it.

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Egg freezing has become quite the watercooler conversation starter this year.

With US tech giants Apple and Facebook announcing plans to financially contribute to employees’ fertility treatments, and last week’s Sunday Night programme profiling the growing number of ‘career women’ freezing their eggs to delay motherhood and pursue professional opportunities, it’s become a fascinating, controversial topic.

At this stage, you probably have a few questions about how it all works and how effective it really is. We did too, so we took them to Associate Professor Peter Illingworth, the Medical Director of IVF Australia, to find out more.

Is egg freezing popular in Australia?

“There’s been a steady growth as more women consider the option of freezing their eggs, but it’s still not a large number of women in Australia who are taking this option up,” Professor Illingworth says.

“The main reason why a woman would do this is so she can have some spare eggs as a backup, should she not be in a position to fall pregnant by herself at an age when it’s practical.”

What are the most common reasons for doing it?

In the vast majority of cases, egg freezing is being undertaken by women who are about to begin chemotherapy for cancer, or who have other medical conditions that can potentially damage their fertility, like endometriosis. This gives them a better chance of pregnancy at a later stage.

However, Professor Illingworth says there have been more women coming forward to discuss the option for non-medical or 'social' reasons. This might be career-motivated, but primarily it's single women who are concerned they might be they might not be in a relationship with the right partner by the time they're ready to have children or when their fertility begins to naturally decrease.

Although women are increasingly considering the option of egg freezing for non-medical reasons, they don't always go through with it. "Some women decide the drawbacks are more than the procedure is worth," Professor Illingworth says.

What about women in relationships? Is it a good idea?

"If a woman came forward to discuss egg freezing and she did have a partner and she was in a relationship, we'd strongly encourage her to firstly consider getting pregnant now, rather than postponing it," Professor Illingworth says.

Freezing embryos rather than eggs would be another recommended alternative, he adds.

Is there an ideal age to freeze your eggs?

Age is a major determining factor of the effectiveness of egg freezing, and whether it's the right thing for a woman to undertake.

"If a woman is 37 or 38 years old by the time she's even considering this, then it's much less likely egg freezing will help her. She needs to start trying to have a family now. If she freezes her eggs and uses them when she's 43 or 44, and they don't work, there's no Plan B at that stage," Professor Illingworth says.

It's a far more realistic possibility for a woman's who's 31 or 32, because she also has the option of using her own eggs at a later stage. (Post continues after gallery.)

It's much less common for women in their 20s to explore egg freezing, and although there's a very high chance of effectiveness, Professor Illingworth says it's often unnecessary for a women of that age to put herself through it unless she has medical reasons.

"Most of the time a woman in her 20s will be reasonably optimistic that she'll be able to have a relationship and conceive by herself. It's only once women get into 30s and they're not in a relationship that those concerns start to grow," he explains.

How does the process actually work?

Every time a woman has her period, one of the numerous eggs that have been growing on her ovaries will be released, and the rest will die. For a cycle of egg freezing, as with a cycle of IVF, hormone injections are used to stimulate all of these eggs to grow in order to be collected. On average, this will amount to 10 to 12 eggs.

Over a 10-day period, a woman will administer these injections every day, and also undergo ultrasound scans and blood test to monitor the growth of her eggs. Once they're ready the eggs will be collected from her ovaries during a small hospital procedure, under local or general anesthetic. They'll then be analysed in a laboratory — the eggs deemed mature will be frozen and stored away.

Professor Illingworth says the number of rounds required depends on how many eggs are collected each time and how many the woman wants to store. He says patients generally aim to store 20 eggs, which can take more than one round to achieve. However, others take the views that any amount of eggs is enough.

When the woman wants to use her eggs, they're thawed and most will be injected with sperm from her partner or a sperm donor (but not all). The fertilised eggs, i.e. embryos, grow in a lab for four days before being transferred into her uterus with the aim to induce pregnancy.

How long can the frozen eggs survive?

Professor Illingworth says with the current technology, the "vast majority of eggs" survive the freezing and storage process, and can remain in storage for a number of years. However, it's not known if there's an upper limit on how long they can stay frozen.

"It appears the big risk to an egg is in the freezing process in the beginning, and in the thawing process at the end. It does not appear at this stage that the time between these two events has an impact on the survival of the egg when it's thawed," he says. (Post continues after video.)

How much does it cost?

Women who have medical reasons to freeze their eggs are eligible for Medicare cover. On average, Professor Illingworth says the out-of-pocket cost in this instance would be $4000.

This isn't the case when the procedure is being undertaken for non-medical reasons, so women exploring this option can expect to pay $10,000-$12,000.

Is it guaranteed to work?

Here's the thing: frozen eggs don't always result in a pregnancy.

"For a woman to freeze her eggs, it's not a guarantee she'll be able to fall pregnant in the future. It gives her an extra option and an extra chance of falling pregnant, but it's not a fail safe insurance policy," Professor Illingworth explains.

The chances of success are related to the number of eggs that are able to be collected, and the woman's age at the time of freezing. At 30, women can expect a success rate of five to eight per cent for every egg she has frozen. For women who are 38 or 40, on the other hand, the likelihood of success is between two and four per cent per egg.

What about embryo freezing?

Embryo freezing — whereby a woman's eggs which have been fertilised with sperm before freezing — has been around much longer than egg freezing, and Professor Illingworth says it's known to have a higher success rate.

"What we think we know is that you can get good success rates by freezing the eggs of younger women, but we're still very uncertain about the likelihood of success for freezing eggs of older women. The success of freezing embryos is likely to be higher than for freezing eggs," he says.

However, embryo freezing is a legally tricky issue. As the DNA from two people is required, each party has a say over what happens to the embryos — so if a couple breaks up after pursuing this option, this can get complex. Under NSW law, neither partner can use an embryo without the other's permission.

This isn't the case for frozen eggs, because they simply belong to the woman.

Is egg freezing safe?

Yes. Professor Illingworth says medically, it's a safe, non-risky procedure to undertake. The bigger question, he adds, is whether it's the right thing for a woman to go through.

Have you ever considered freezing your eggs? Why/why not?