Egg freezing is advertised as an ‘insurance’ against age-related fertility decline and the number of healthy Australian women keen to preserve their fertility as they get older is on the rise. Despite this, there is little information available to guide women. This six-point guide tries to redress this lack of advice using the latest evidence.
1. Eggs should be frozen when you are young, but not too young
In Australia, the median age of mothers has increased from 25.4 years in 1971 to 30.8 today. The average age of women freezing their eggs is around 37, with many women freezing their eggs in their late 30s and early 40s. However, the highest live birth rates from previously frozen eggs come from women who undergo the procedure before they are 30, when eggs are high-quality.
Freezing eggs is expensive, so although freezing your eggs in your early 20s may result in a good number of high-quality eggs being frozen, you are unlikely to know at this age if you will ever need to use them, and you may, instead, conceive naturally.
2. Eggs can only be stored for 10 years in some states
Another reason why women may not want to freeze their eggs when they are too young – in their early 20s –is that some states in Australia have a storage time limit of 10 years.
You can obtain an extension to the storage period, allowing the eggs to remain frozen for up to 55 years, but only if you can demonstrate that you have become prematurely infertile.
3. Choose carefully, not all clinics are equal
If you are thinking about freezing your eggs, find a clinic that has plenty of experience with the procedure. You should also ask the clinic if they are able to provide you with success rates with egg freezing from their own data.
Some clinics provide average figures based on published data from other clinics. You should also ask to see success rates by age, as the likelihood of achieving a live birth with eggs taken from a 32-year-old is likely to be very different to a live birth with eggs taken from a 39-year-old.
4. You are likely to lose eggs along the way
The more eggs you freeze, the more likely you are to have a live birth in the future – as long as the eggs are a good quality. Recent data suggests that to have a 75% chance of having one live birth, a 34-year-old would need to freeze ten eggs. But a woman undergoing the procedure at 37 would need to freeze 20 eggs, and a woman aged 42 would need to freeze 61 eggs to have the same chance of success.
Eggs are lost throughout the process of egg freezing. For example, a 36-year-old woman could produce 15 eggs following stimulation, but some of these eggs may be immature and therefore unsuitable for freezing. Some of these eggs might also not freeze or thaw correctly, may not fertilise, or may not reach blastocyst stage (the stage suitable for implantation). At the end of the process, there may be just four embryos with which to attempt conception.
The birth rate with previously frozen eggs per embryo transfer is around 19%, which means that it is possible, even with four embryos, that the procedure might not result in a live birth.
5. It's expensive and you might need to have the procedure many times
There is no Medicare rebate for egg freezing in Australia. The costs of egg collection and freezing vary between clinics but expect to pay $7,000-10,000 per round and about $500 per year for storage. There will also be costs involved when you return to use your eggs.
Research suggests that women should seek to freeze around 15 eggs to have a reasonable chance of future pregnancy. However, the number of eggs collected during one cycle of stimulation and retrieval depends on the woman’s age at the time of undergoing the procedure, her remaining ovarian reserve, and how she responds to the stimulation. As such, some women may produce 15 eggs for storage after one round of treatment whereas others may need to undergo multiple rounds of stimulation and retrieval – with the associated costs – to collect and freeze the same number of eggs.
As well as being expensive, the process of egg freezing and IVF can often be emotionally and physically challenging. It is important to bear this in mind when considering freezing your eggs. Women should freeze around 15 eggs to have a reasonable chance of future pregnancy.
6. Only 6% of women actually use their frozen eggs, and a fraction of those result in live births
Dr Karin Hammarberg led a study in 2016 that showed only 6% of women who froze their eggs returned to use those eggs. A more recent Belgian study found similar results – less than 8% of women who froze their eggs went back to use them. And only one in three of them successfully had a child.
The cumulative live birth rate of egg freezing – which assumes several attempts at IVF with previously frozen eggs – is still only around 20% for women who froze eggs when they were 36 years of age. And even when using young, previously frozen eggs to conceive, as seen in donor cycles, older women are still at a higher risk of complications during pregnancy and birth than women attempting motherhood at a younger age.
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Dr Kylie Baldwin is a sociologist with an interest in women’s health, reproduction, (in)fertility, reproductive ageing, gender and reproductive biomedicine. She is a Senior Lecturer at De Montfort University in the UK. Dr Karin Hammarberg is a Registered Nurse with 20-years experience as clinical co-ordinator of IVF programs. She is a Senior Research Fellow in the Jean Hailes Research Unit, School of Public Health & Preventive Medicine at Monash University.
