Women who freeze their eggs over the age of 40 are highly unlikely to end up with a baby, a study suggests.
Hollywood actress Sienna Miller revealed last year that she had frozen her eggs aged 40 to avoid the ‘existential threat’ of her ticking biological clock.
But a new study suggests the odds of success are tiny for women who freeze their eggs in their forties, despite women in Britain undertaking the fashionable procedure up until the age of 49.
A research team led by Imperial College London looked at all 373 women who froze their eggs over a decade at one of the largest private clinics in London, the Centre for Reproductive and Genetic Health (CRGH).
Around one in 10 women returned to thaw their eggs and attempted to have a baby through IVF.
Hollywood actress Sienna Miller revealed last year that she had frozen her eggs aged 40 to avoid the ‘existential threat’ of her ticking biological clock
The graph, from the London Egg Bank and not affiliated with the new study, shows the number of IVF live births per embryo transfer by age group. It shows that success rates plummet after the age of 40 among those using their own eggs, and fall more gradually among those using donor eggs
A new study by a research team led by Imperial College London, suggests the odds of success are tiny for women who freeze their eggs in their forties. This is despite women in Britain undertaking the fashionable procedure up until the age of 49
Among those who were in either their early or late thirties when they froze their eggs, around a third were able to have a baby using the eggs.
But zero per cent of women who were aged 40 or older at the time of egg-freezing ended up with a baby when those who froze their eggs between 2008 and 2018 were followed up.
Although two women fell pregnant in this period after freezing their eggs over the age of 40, they suffered miscarriages, which are far more common in older women.
The study from the London clinic is relatively small because, despite the popularity of egg freezing, few women go back to use their eggs – for reasons such as becoming pregnant naturally or not meeting the right person to start a family.
But the new results echo similar research from two UK clinics, published in 2019, which looked at 129 women who froze their eggs over a decade and sought to use them to start a family.
This previous study showed just seven per cent of women aged 40 to 42 when they froze their eggs ended up with a baby or ongoing pregnancy.
The new study concludes that women who freeze their eggs over the age of 40 are ‘unlikely’ to succeed when they try to have a baby.
Dr Lorraine Kasaven, first author of the study from Imperial College London, said: ‘It is important to counsel women aged 40 or above having egg freezing of the realistic expectation of poor outcomes, such as low live birth rates, as this study shows.
‘Although this was a small study, from a single centre, only up until 2018, it is important to understand that when women return to use their eggs, this does not guarantee they will have a baby.’
If women freeze their eggs when they are younger, the eggs are typically better quality, so are more likely to lead to a pregnancy when women use them for IVF later in life.
Egg-freezing is therefore increasingly popular among single women, or those deferring motherhood to focus on their career, despite the eye-watering average cost of £8,000 for freezing and thawing eggs.
Miss Miller, who has a 10-year-old daughter, Marlowe with her ex-partner, actor Tom Sturridge, told Elle magazine last year: ‘[I felt] pressure [about] kids, and should I have more, and why haven’t I, and all of that, which is a really loud noise.’
After freezing her eggs, she said the ‘existential threat has dissipated’.
However eggs frozen when women are over 40 tend to be poorer quality.
The new study, published in the journal Archives of Gynaecology and Obstetrics, found 9.7 per cent of women at the CRGH clinic in London returned to use the eggs they had frozen – just over three-and-a-half years after freezing them, on average.
In the decade between 2008 and 2018, the clinic saw a total of 36 women return to use their eggs.
However all 11 IVF cycles attempted by women over 40 were unsuccessful.
That compared to a 37.5 per cent success rate for women aged 36 to 39, who had 10 babies from 24 attempts, and a 33 per cent success rate for women 35 and under, who produced two babies from six attempts.
Dr Jara Ben Nagi, senior author and a consultant gynaecologist and specialist in reproductive medicine at CRGH, said: ‘Egg-freezing is most likely to help women have babies if they do it before the age of 36 as, after that, the chances of having a baby are significantly reduced and the risk of having a miscarriage is also higher.’
The most common age at which women freeze their eggs is currently 38.
