First Human Egg ‘Rejuvenation’ Offers Hope for Older IVF Patients

For women over 35 undergoing IVF, the statistics are sobering: ~35% of all their eggs contain abnormal chromosome numbers (aneuploidy), a primary driver of treatment failure and miscarriage. The figure rises to ~90% at age 44. Research presented in Edinburgh this week at the British Fertility Conference suggests this age-related defect might be reversible, marking what could be the first successful rejuvenation of human eggs.

Ovo Labs, a Munich-based biotech startup focused on improving IVF outcomes, has revealed first-time efficacy data showing that microinjections of a single protein, EmbryoProtect 1 (EP1), can significantly reduce chromosome abnormalities in eggs donated by fertility patients. The treatment targets a vulnerability that emerges as eggs age, when the molecular ‘glue’ holding chromosomes together begins to weaken.

In a preclinical study involving over 100 eggs from patients aged 22 to 43, admittedly a small sample size for a preclinical trial, the proportion of eggs showing defects dropped from 53% in control samples to 29% in those receiving the protein injection. For women over 35, the improvement was similarly pronounced, though statistical significance was limited by the small sample size of just nine eggs in this age group. Although this data has not been through peer-review yet, these findings are of great importance to IVF for women with repeated problems in IVF.

‘Overall we can nearly halve the number of eggs with [abnormal] chromosomes. That’s a very prominent improvement,’ said Prof Melina Schuh, a director at the Max Planck Institute for Multidisciplinary Sciences in Gottingen and co-founder of Ovo Labs. ‘Most women in their early 40s do have eggs, but nearly all of the eggs have incorrect chromosome numbers. This was the motivation for wanting to address this problem.’

The findings are generating cautious optimism among the scientific and fertility community, and, of course, experts are rightly calling for more comprehensive data before drawing firm conclusions. Professor Richard Anderson, Elsie Inglis Professor of Clinical Reproductive Science at the University of Edinburgh, called the results potentially transformative. "Being able to treat eggs to make this process work better would be a huge advance, and is what Ovo Labs are claiming to be able to do," he said, though he cautioned that "the details are rather sketchy" and emphasized the need for confirmatory clinical trials addressing safety issues.

The decline in egg quality drives a steep drop in IVF success rates as women age. The problem stems from meiosis, the specialised cell division that occurs in sex cells. But in older eggs, Schuh’s team has discovered, the chromosome pairs begin loosening at their midpoint well before fertilisation. This causes the X-shaped structures to drift chaotically rather than lining up properly, resulting in uneven splits that produce embryos with too many or too few chromosomes - aneuploidy. This leads to failed implantation, miscarriage, or chromosomal disorders like Down syndrome.

Schuh and colleagues previously identified that a protein called Shugoshin 1 (SGO1), which appears to function as a molecular glue for chromosome pairs, declines sharply with age. Their latest experiments in both mouse and human eggs suggest that restoring this protein through microinjection can reverse the premature separation problem. Professor Robin Lovell-Badge of the Francis Crick Institute recognised the significance of these early results and, interestingly, was keen to understand why Schuh’s lab focused on SGO1 rather than SGO2 as previous research has indicated that there is a clear link between SGO2 and age-related aneuploidy.

Dr Güneş Taylor of the University of Edinburgh, who was not involved in the research, described the findings as "really promising.", noting that "if there's a one-shot injection that substantially increases the number of eggs with properly organised chromosomes, that gives you a better starting point." 

Ovo Labs was founded in 2025 by Schuh along with co-CEOs Dr Agata Zielinska and Dr Oleksandr Yagensky, and is now working toward clinical trials. The company builds on more than two decades of research from Schuh's laboratory, which has published extensively on egg biology in top-tier journals including Science, Cell, and Nature.

Dr Zielinska emphasized the potential impact for patients who currently face repeated IVF cycles with limited prospects for success. "Currently, when it comes to female factor infertility, the only solution that's available to most patients is trying IVF multiple times so that, cumulatively, your likelihood of success increases," she said. "What we envision is that many more women would be able to conceive within a single IVF cycle."

If validated in clinical trials, the EP1 treatment could result in an additional one million babies born through IVF annually worldwide, potentially the most significant advance in IVF success rates in decades. Professor Antonio Pellicer, founder of IVRMA, the world's largest IVF clinic network, described the approach as "scientifically grounded and could not be more clinically relevant."

Aside from intracytoplasmic sperm injection (ICSI), there are currently no treatments involving microinjections into eggs, but Schuh's team does not anticipate major safety hurdles and is in discussions with regulators about trial design. A critical question for future research will be whether the observed improvements in chromosome organisation translate into embryos with fewer genetic errors and, ultimately, higher live birth rates.

The approach would not extend fertility beyond menopause, when the ovarian reserve is depleted. However, for the growing population of women attempting conception in their late 30s and 40s, the prospect of improved egg quality represents a potential paradigm shift in reproductive medicine.