Egg freezing success rate hits 26 per cent as the average age for starting IVF rises to 35

Freezing eggs to use in fertility treatment years later has similar success rates to routine IVF, a major study suggests.

In one of the UK’s largest-ever analyses of the practice, researchers tracked the outcome of almost 30,000 eggs that were frozen at a clinic between 2008 and 2022.

They found the treatment had an overall live birth rate of 26 per cent, with success highest among those who had their eggs frozen under the age of 35.

This compares with success rates of 31 per cent of fresh embryo transfers, according to the latest figures from the Human Fertilisation and Embryology Authority.

The study analysed treatment outcomes for 299 patients who had frozen their eggs and returned for fertilisation and pregnancy, typically around two years later.

These resulted in 93 clinical pregnancies and 77 healthy live births, according to the findings published in Reproductive Biomedicine Online.

Average age for women to begin IVF is now 35

The egg-freezing success rate rise comes as new data shows the average age of women starting IVF is now 35 – despite the chances of its success declining as they get older, according to the fertility regulator.

Increasing numbers are also using egg-freezing to delay motherhood, a report by the Human Fertilisation and Embryology Authority found.

The data showed that women starting fertility treatment are now typically almost six years older than those having their first babies naturally.

The trend has been blamed on long waiting lists, COVID delays and the prohibitive costs of private treatment.

The report revealed that increasing numbers of women are also using IVF to become single parents, seeing an 82 per cent leap.

Using previously frozen eggs and embryos to try for a baby years later is the fastest-growing fertility treatment in the country, the authors of the annual report note. HFEA chairman Julia Chain warned that “fertility treatment is not a guarantee of having a baby”.

“IVF success rates continue to improve, but as the chance of a birth rapidly decreases with age, early access to fertility treatment is crucial for those who need it,” she said.

“It is important to seek advice about fertility so if treatment is needed, patients can access it as soon as possible to reduce delays.”

Despite the rising age of patients, IVF advances have seen the overall pregnancy rate using fresh embryo transfers and patients’ own eggs increase from 21 to 31 per cent between 2012 and 2022.

Women aged 18 to 34 had the highest pregnancy rate per embryo transferred, with 42 per cent successful.

This fell to 34 per cent in those aged 35 to 37 – now the greatest proportion of patients – 26 per cent in 38 to 39-year-olds, 16 per cent for those aged 40 to 42 and 9 per cent in 43 and 44-year-olds.

While these figures are all improvements – up from 22, 17, 10 and 5 per cent respectively – experts urged couples to try to start treatment sooner to boost their chances.