Vali, a woman from Brisbane, Queensland, Australia, asked doctors to preserve some of her ovarian tissue while she was undergoing cancer treatment in case it was possible to graft it back in the future.
"It didn't really hit me until I was ... 24 and I had to make some serious decisions about my healthcare then," she said. "I was really lucky with my doctors. I was able to have this opportunity even though I didn't really know anything about it."
Associate professor Kate Stern, head of fertility preservation at Melbourne IVF, said she consulted with Vali's surgeon and oncologist before attempting the first graft in 2010.
A second graft was done two years later.
"The tissue was put back in the front wall of her abdomen, so that means it's under the skin and the muscle but not inside the abdomen," Stern said.
"We wanted to see if this might help her get pregnant. Then we gave her some very gentle hormone stimulation -- not the full-on IVF."
The process produced two eggs, which where later fertilized and put back inside Vali's uterus. The 24-year-old cancer survivor and her partner, Dean, are now expecting twins.
Stern said when they began the procedure it was "unlikely" that it would be successful.
"There have been 29 babies born in the world [using this procedure]," he said. "But that's all from tissue that's been grafted back into the ovary or close to the ovary. But still, with that 29 there have been multiple, multiple, multiple attempts."
Stern said there was a big team of people behind the breakthrough.
"It's amazing how everyone is so excited for our patient. We've been doing this for a long time now, so it's taken a while to get to this point."