Women could be mothers at 50, say Israeli scientists who have successfully ‘reverse-aged’ human eggs.
In a major breakthrough, Israeli researchers effectively made eggs from 40-year-old women resemble those of 20-year-olds.
Women are born with all of their eggs but they deteriorate over time, making it more difficult for older eggs to be fertilised.
While the average female in her early 20s has an 80% chance of becoming pregnant naturally within a year, this halves by the age of 40.
Just a few hundred women in the UK become mothers in their 50s each year.
Scientists at the Hebrew University of Jerusalem have shown the deterioration could be reversed with an antiviral used to treat HIV patients.
It is thought to work by preventing DNA damage that happens during the ageing process with a drug that blocks genetic damage during viral infections.
Following this success, the team now plans to test it on animals and eventually humans. It is also hoped the treatment could reduce the risk of miscarriages and birth defects, which are more common with older mothers.
During the ageing process in a human egg, parts of its DNA can start attacking other areas in a similar way to how viruses can replicate. To stop this, the scientists theorised that an antiviral called a reverse-transcriptase inhibitor used to prevent DNA damage in viral infections could help.
‘Many women are trying to get pregnant aged 40 and over, and we think this could actually increase their level of fertility,’ Dr Michael Klustein, the molecular biologist who led the research, told the Times of Israel.
‘Within 10 years, we hope to use antiviral drugs to increase fertility among older women,’ he said.
Klustein explained that the attacking DNA behaves like a virus so the antiviral medicine administered to eggs worked in reverse ageing them.
The drug was first tested on hundreds of mice embryos, before being used on leftover human embryos from IVF treatments. The team claimed in a press release that the older mouse eggs that were treated ‘returned to their former youthful selves’.
A 2020 study by the Office for National Statistics (ONS) showed that women are choosing to have children much later than previous generations.
In the UK, the average age of first time mothers is now 29 years old — compared to 23 in the 1970s — with many delaying having children, well into their 30s.
The change can be attributed to increased choice and autonomy but also financial worries. However, studies suggest that the chances of getting pregnant is as low as five per cent once a woman is over 40.
To get around this, many women are now having eggs frozen when they are younger in preparation for fertility treatment later in life. About 50,000 women use fertility treatment every year in the UK, while in the US it is more than 90,000.
Success rates for IVF treatment are about 25% — or one in four embryos — for women aged between 35 and 37 years old. For those under 35, success rates are about 32%
However, the scientists behind the study stressed that they have not yet tested introducing sperm to the treated eggs, so its yet to be proven if it enhances fertility.
The study was published in the journal Aging Cell.
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