Woman’s reproductive system. Credit: SewCreamStudio, Shutterstock
New Barcelona-based research released on July 17, 2025, reveals why female reproductive cells last so long. This article discusses whether spending thousands on freezing eggs is really worth it.
A study published in The EMBO Journal and reported by ScienceDaily on July 17, 2025, has revealed that human eggs deliberately slow down their internal “waste disposal” systems to stay healthy for decades. This energy-saving trick appears to protect them from ageing and could change how we approach fertility treatments like IVF.
“By looking at more than a hundred freshly donated eggs, the largest dataset of its kind, we found a surprisingly minimalist strategy that helps the cells stay pristine for many years,” said Dr Elvan Böke, Group Leader at the Centre for Genomic Regulation (CRG) in Barcelona and lead author of the study.
The study collected over 100 eggs from 21 healthy donors aged 19-34 at Dexeus Mujer, a Barcelona fertility clinic, 70 of which were fertilisation-ready eggs and 30 still-immature oocytes. The research is the largest-scale study of healthy human eggs collected directly from women.
Using live imaging and fluorescent probes, researchers discovered that mitochondria, proteasomes and lysosomes – the cells’ “housekeeping” machinery – work at 50 per cent of their normal rate. This reduced metabolic activity likely lowers the production of reactive oxygen species (ROS), which are known to damage DNA over time.
This “standby mode” not only conserves energy but appears to be a natural longevity hack. Eggs even eject lysosomes into the surrounding fluid just before ovulation, like a “spring cleaning” to stay fresh, said first author Dr Gabriele Zaffagnini.
What about egg freezing?
Some egg freezing cycles can cost thousands of euros. But is it worth it?
A separate report from the Progress Educational Trust (PET), published in 2022, asks exactly that. Egg freezing has been heavily marketed in recent years as an “insurance policy” for women wanting to delay pregnancy. But even prominent fertility experts warn against over-promising results.
In the report, Professor Robert Winston is cited slamming some fertility clinics as being “highly exploitative,” warning that the idea of freezing eggs “is a scam” because it “almost never leads to a successful birth.”
The report highlights these concerns, especially given that freezing often happens later in life when egg quality is already compromised. Some UK clinics have even launched “freeze and share” schemes where women can get discounted freezing in exchange for donating eggs to others – a move seen by some as unethical.
While success rates have improved since the American Society for Reproductive Medicine (ASRM) removed the “experimental” label in 2012, they still remain relatively low, especially for women over 35.
In 2015, the Japan Society of Obstetrics and Gynaecology decided not to recommend egg freezing for healthy women due to health risks and low pregnancy rates.
IVF supplements
The new Barcelona study may also challenge one of IVF’s most common practices – the pushing of supplements to improve egg health.
“Fertility patients are routinely advised to take random supplements to improve egg metabolism, but evidence for any benefit for pregnant outcomes is patchy,” said Dr Böke. “By looking at freshly-donated eggs we’ve found evidence to suggest the opposite approach – maintaining the egg’s naturally quiet metabolism – could be a better idea for preserving quality.”
The researchers now plan to examine eggs from older donors and failed IVF cycles to see if these cellular energy-saving procedures weaken with age.
This discovery opens new possibilities in reproductive science, but it also raises uncomfortable questions: If eggs can stay viable on their own, are women being sold false hope through costly egg freezing? Should clinics be legally required to publish their success rates clearly? And are women really being empowered, or just emotionally marketed to?
A growing number of women are turning to egg freezing over 40, when success rates are known to be lowest.
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