When 38-year-old Melbourne woman Sarah looks at her one-year-old baby, Etta, she sees a precious gift that she and her husband might never have been granted.
"Sometimes I look at her and I think it's just sort of incredible that it actually happened," Sarah told ABC's 7.30.
In 2009, Sarah was diagnosed with Hodgkin's lymphoma and was told she had to start treatment straight away.
From that moment, her focus was solely on her own survival and not on bigger questions about how treatments such as chemotherapy might affect her body and her future chances of falling pregnant.
"At the time, the main things I was worried about were, 'Am I going to die?' And things like, 'Is my hair going to fall out?'" she said.
"Secondary issues — [such as] 'What's the long-term impacts on my fertility and my other health?'— were sort of really in the back of my mind."
Luckily, her mother thought to ask those questions before Sarah started chemotherapy and she was put in touch with Dr Kate Stern, who runs an innovative fertility program at the Royal Women's Hospital in Melbourne that, a decade later, helped change the course of Sarah's life.
"Without my mum making that phone call, and all these pieces falling together, [Etta] just might not have ever existed," Sarah said.
Science behind innovative procedure
When ABC's 7.30 met Sarah, baby Etta was waddling around happily on the floor. She had taken her first steps that morning and turned one the day before.
Those are special milestones for any family, but even more so for Sarah and her husband, Gabriel, who had been through a long and difficult journey over a period of 10 years to get there.
As Sarah underwent treatment for cancer immediately after her diagnosis, there was no time for conventional procedures such as egg freezing. So she and Dr Stern decided to use another innovative method to give Sarah the chance to fall pregnant when she concluded her cancer treatment.
It's known as ovarian tissue freezing, and Dr Stern was one of the doctors who helped pioneer the procedure at the Royal Women's Hospital.
"Fertility preservation with ovarian tissue is innovative and it's exciting but, because of the technical difficulties, it's not widely available around the world, " Dr Stern said.
The procedure involves removing part of a woman's ovary tissue via keyhole surgery, slicing it thinly and then freezing it in special containers in a lab.
When the woman completes her cancer treatment, the tissue can be defrosted and inserted back into her abdomen if she decides she wants to try to start a family.
"Over four or five months, that tissue gets a life of its own, it gets new blood vessels, the follicles and eggs start to develop. And it makes hormones — it is absolutely miraculous, we think," Dr Stern said.
'For these patients, it's this versus nothing'
Dr Stern helped set up the program at the hospital and played a key role in developing the procedure 26 years ago.
While the treatment is no longer considered experimental, it is highly specialised and cannot be performed at all hospitals, and Dr Stern cautions that it does not guarantee a patient can fall pregnant.
"Getting good eggs is still hard work," she said.
"But the treatment is quite successful. It depends what your benchmark is but, for these patients, it's this versus nothing."
Dr Stern said that, around the world, about 170 women have fallen pregnant after using their frozen ovarian tissue.
In Sarah's case, her cancer treatment stretched out from a few months to a decade of on-and-off treatment that took a heavy toll on her body.
"Sarah's extensive treatment for her cancer damaged her ovaries so that she was in a state of what we call premature menopause — her ovaries did not have any good eggs in them," she said.
"So Sarah needed to have this ovarian tissue grafted to be able to have any opportunity [of having] a baby."
When Sarah was two years in remission, she was advised it was safe to reinsert the ovarian tissue and to try to fall pregnant.
A few years later, in July 2021, Etta was born.
'We had no idea about these options'
Over in the remote town of Streaky Bay in South Australia, 11-year-old Zahli Habel is at a very different stage in her life.
She finished her chemotherapy a year ago but, before she began, she had part of an ovary removed and flown to the Royal Women's Hospital in Melbourne to be frozen and preserved if she decides to have children in the future.
"Zahli was diagnosed with a cancer that required intensive chemotherapy. This chemotherapy has a high chance of damaging future ovarian function," Dr Stern explained.
The diagnosis was shocking enough for Zahli and her family, and fertility was not something they had considered.
"I guess when we got the diagnosis, we were dealing with that — that was the biggest issue," Zahli's mum, Steph, said.
"And then, suddenly for them to come out and talk about fertility … we had no idea about these options.
"And it was amazing that it was offered to us and that we could take it up."
Zahli decided that it was a good option for her to give her choices in her future.
"I knew I had to do it," she said.
"Because, if I wanted to have kids in the future and chemo killed off all my eggs, I knew that was really my only thing to rely on."
