In an Australian first, a woman has become pregnant after being reimplanted with ovarian tissue she opted to have frozen 7 years earlier before treatment for cancer, according to a case report published online today in the Medical Journal of Australia.

The woman, who was 37 when her breast cancer was found, opted for the cryopreservation procedure before starting gonadotoxic chemotherapy which would severely reduce her chances of falling pregnant.

At the age of 43, wishing to become pregnant but menopausal on testing, she decided to have the preserved tissue reimplanted in her ovaries. Several months later when it became clear that she was ovulating again, the woman underwent in-vitro fertilisation treatment, and in November of 2012 an ultrasound revealed a healthy 6-week-old fetus. She is now in her second trimester.

Professor Gabor Kovacs, International Medical Director, and colleagues from Monash IVF announced the landmark pregnancy in the MJA, saying it was the first in Australia to occur after both cryopreservation and autotransplantation - the process of regrafting removed tissue. "The pregnancy reported here is one of the first 20 of its kind in the world, and only the second in a woman successfully treated for breast cancer," they wrote.

The procedure offers new hope to women whose fertility may be threatened by cancer treatments. "[This procedure] has the advantage that the ovarian tissue can be collected within 24 hours, no hormones need to be administered at the time of the cancer diagnosis, and the procedure takes less than half an hour and can be performed by any gynaecologist.

"The process at the time of cancer diagnosis is also relatively inexpensive, as it only requires an operative laparoscopy and a few hours of a laboratory scientist's time." The authors said the one concern with ovarian tissue reimplantation in women diagnosed with cancer - the risk of retransplanting malignant cells - was "minimal" with breast cancer as "the tiny pieces of ovarian tissue would be most unlikely to contain metastatic cancer cells".

"There is also a possible application of this technique in delaying or avoiding menopause", they concluded.