IVF breakthrough: frozen eggs as good as fresh

As more women than ever choose to freeze their eggs, advances in IVF techniques mean survival and fertility rates match those of fresh eggs.

Primary school teacher and single mother Selina Rutko, 42, with her six-month-old baby daughter Tahnee who was conceived using IVF. Picture: Alex Coppel

The survival and fertility rates of a woman’s eggs that have been frozen are almost as high as those for fresh eggs, a new study has shown.

A longitudinal study by Melbourne IVF of more than 30,000 eggs across 3280 elective egg ­cycles from January 2013 to December 2022 recorded a 92 per cent survival rate and 65 per cent fertilisation rate across the frozen eggs. This is in line with the fertilisation and embryo development of fresh eggs.

Selina Rutko, 42, is a primary school teacher and a single parent who conceived her child, Tahnee, using IVF. Tahnee is now six months old and Ms Rutko has been a proponent of egg freezing services since.

“I didn’t want to miss the opportunity to become a mother,” Ms Rutko explained.

“It took a bit of courage to do it, because you’ve got to get your mindset right.”

Ms Rutko first froze her eggs at age 36 and said it allowed her to decide when she was ready to be a parent.

“I really wasn't ready before. Then it was just a feeling that this was the right time for me. I think everybody has to get to that ­moment,” she said.

“You don't realise just how many people are thinking about it who are not speaking about it. It’s very private and very personal.”

Professor David Gardner from Melbourne IVF has a 40-year career in medicine that was recognised with a lifetime achievement award from the Society of Reproductive Biologists and Technologists this week.

Professor Gardner said the efficacy of this procedure provided “enormous flexibility” to users.

“We’re living longer lives and our healthspan is increasing. Unfortunately, our reproductive ageing is still the same and it’s very short,” Professor Gardner said.

“Our capacity to reproduce really is a very short period of our lives. So egg cryopreservation is really maximising a woman’s ­fertility potential by being able to stop the biological clock, as it were.”

The Melbourne-based researcher attributed the rising ­viability to improved freezing techniques. Where previously reproductive scientists used slow freezing where eggs were slowly dehydrated, the preferred process now is vitrification, where eggs are rapidly cooled to -196C.

Slow freezing would often allow ice crystals to form in eggs, which was a hazard that impinged on the survival rates of eggs, but vitrification does not carry that same risk of ice formation.

“Biology is never a certainty, I wish it were. But what this study does give us is valuable information to talk to patients about realistic probabilities of their success (in IVF),” he said.

“We can now counsel the ­patients on how many eggs will be required to attain the probability of a pregnancy.”

The study is one of the first to analyse the long-term viability of egg freezing, observing mature eggs outside of per-cycle survival rates.

“If a woman elected to freeze her eggs at the age of 35 and came back to use her frozen eggs when she was 41 years old, the pregnancy success rates of the thawed eggs will be equivalent to that of a 35-year-old using fresh eggs,” said John Stevens, director of the assisted reproductive technologies laboratories at Melbourne IVF.

“By freezing eggs, it pauses ageing. This study provides reassurance to patients and doctors that elective egg freezing pregnancy results are close to that of patients using fresh eggs.”

Egg freezing has risen rapidly in popularity over the past 15 years, with Monash University reporting a 1000 per cent rise in egg freezing operations between 2011 and 2020. In 2021, there were a total of 5881 fertility preservation cycles conducted, a 62 per cent increase on 2020.

In the future, researchers want to experiment with adding antioxidants to the protective solution eggs are vitrified in, as animal trials suggest this could improve results even further.