Freezing eggs: When is the best time?

Filip Vukasin

9/02/2023 3:26:46 PM

The most logical time to freeze eggs may differ from when egg quality is best, according to an Australian review of the data.

Eggs being preserved via vitrification.
The most balanced and logical time to freeze eggs is between 32–38 years of age, experts say.

In recent years, the age of first-time mothers in Australia has been increasing.
Between 2010–20, the average of people giving birth for the first time went from 28.3 to 29.6 years, while 36% of all births were among those aged between 30–34.
Given the trend of later first-time pregnancy and births, an Australian review published in the Australian Journal of General Practice has offered insight into the best timing for egg freezing.
And while eggs are typically healthier at a younger age, the authors have instead asserted that the most balanced and logical time to freeze eggs is between 32–38 years of age.
The reason for this, according to fertility specialist and lead author Associate Professor Alex Polyakov, is that even though younger eggs are more likely to produce live births, they are much less likely to be used.
‘When you’re younger, it’s easier to get more eggs and better quality,’ he told newsGP.
‘However, the majority won’t be used and they will get pregnant naturally or choose not to have children.’
This is because they have more time to find a partner or plan for other ways to have children, Associate Professor Polyakov says.
On the other end of the scale, freezing at an advanced age, such as over 40, is unlikely to be successful.
‘As age increases, the chance of pregnancy per egg decreases with the quality of oocytes reducing,’ Associate Professor Polyakov said.
Some of the statistics cited in the review include:

  • A 32-year-old woman with five frozen eggs has a 55% chance of live birth
  • A 32-year-old woman with 25 frozen eggs has a 98% chance of live birth
  • A 38-year-old woman with five frozen eggs has a 26% chance of live birth
  • A 38-year-old woman with 25 frozen eggs has a 77% chance of live birth
‘So, if you want the same overall chance at 38, you will need more eggs than if you were 32,’ Associate Professor Polyakov said.
He adds that unlike preimplantation genetic testing (PGT) for embryos, there is no current technology to check the quality of eggs.
‘Eggs are checked for maturity and only the mature ones are frozen, but in terms of quality, there is no way of knowing,’ Associate Professor Polyakov said.
‘It’s important to counsel women that freezing eggs isn’t a guarantee that it will produce a baby.
‘If you freeze 20 eggs, some won’t be able to be frozen, most will survive thaw but perhaps not all will fertilise, some won’t progress to be viable, and so there is some attrition with every step in the process.’
He says current medication protocols have reduced the risk of ovarian hyperstimulation syndrome, and other risks with egg freezing such as bleeding, pelvic infection and organ damage are low.
In terms of risks to children borne of egg freezing, the data is relatively new but reassuring.
‘So far, the [child] outcomes are almost identical to fresh eggs,’ Associate Professor Polyakov said.
‘Egg freezing has been around a very long time but with the egg being the biggest cell in the body, it is full of water.
‘With slow freezing, it expanded and sometimes the cell would blow up [with this] technique which didn’t work well. With vitrification, which has been around 10 years, it’s a snap freeze and so has no chance of ice crystals and survival of frozen eggs is very good.
‘Most kids [from vitrification] are under 10 and there aren’t any issues.’
The American Society for Reproductive Medicine removed the ‘experimental’ designation from oocyte vitrification in 2012 with Australian guidelines in 2019 echoing the sentiment.
One emerging area of discussion is whether egg freezing should be publicly funded to allow greater access.
Dr I-ferne Tan, a fertility specialist and obstetrician/gynaecologist, told newsGP publicly funded egg freezing would allow access to younger women who generally have less ability to pay for it.
‘This is a huge area of preventive medicine. Some people spend a lot of money for IVF in later life,’ she said.
‘So freezing eggs at a younger age is a type of preventive medicine and would reduce a woman’s chances of having to go through multiple cycles of IVF at a later stage.
‘For proven subfertility and other conditions, a woman might pay around $10,000 and get about half of that back from Medicare. For social freezing, you’re not getting any rebate and the medications cost about $2000. You pay for it all out of pocket.
‘Which 20-something can afford that?’
Associate Professor Polyakov says there is broad support for publicly funded egg freezing.
‘There was a paper recently saying 60–70% of people support this idea,’ he said.
‘It’s not a bad idea because in the long term it might help save money in the health system to avoid IVF procedures.
‘If it’s publicly funded and younger women start taking up the option, there will be a lot of eggs frozen but the majority won’t be used, so the controversy is cost effectiveness.
‘Part of our agenda is to say those women should be encouraged to donate their eggs to someone who needs them as this helps with cost effectiveness.’
Dr Tan says educating young people about egg freezing is paramount.
‘Education is important. How many young women know about freezing their eggs?’ she said.
‘I was a junior doctor and an obstetrics trainee, and I didn’t consider freezing my eggs. I only thought about it once I was later in my training but by then I already had a partner and was planning a pregnancy.’
Professor Polyakov agrees and says most patients seeking egg freezing are in their mid-30s.
‘I would like it to be a bit less, very early 30s would be ideal. There needs to be more education to get women to look at it around 30.
‘They’ll have better eggs, more eggs and the chances of success are higher.’
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