By Maxine Frith
San Antonio, Texas - Scientists have made the most important breakthrough in treating female infertility in decades, completing an experiment which could reverse the effects of menopause, allowing childbearing to be extended almost indefinitely.
Researchers in America say they have transplanted ovarian tissue into a rhesus monkey, harvested the resulting eggs and fertilised them in a laboratory. The embryos were replanted into the monkey, which gave birth to a healthy female.
Although ovarian transplants resulting in live births have already been done in rats and sheep, it is the first time the procedure has been completed in a species so closely related to humans. The results, to be published in a medical journal next month, could lead to similar operations in humans in 10 years.
The breakthrough gives new hope to young women with ovarian cancer or left infertile by radiotherapy. It also means women who begin menopause early could have healthy ovarian tissue removed and preserved for replanting. Nearly 7 000 UK women are diagnosed with ovarian cancer each year while 100 000 experience early menopause.
David Lee, who led the research at the Oregon National Primate Research Centre, said: "This procedure has utility for preserving the reproductive potential of cancer survivors and treating menopause and suggests ovarian tissue banking in humans may be feasible."
The breakthrough raises serious questions about the ethics of allowing women who have gone through menopause to have children.
At present, women with cancer and at risk of becoming infertile can have their eggs removed and stored. But older eggs have less chance of pregnancy. The study means healthy ovarian tissue can be preserved almost indefinitely and new eggs produced.
Jack Scarisbrick, chairman of campaign group Life, said: "This is about cheating nature. It is a further example of how human procreation is being turned into a procedure in a laboratory when nature has dictated fertility is not possible."
For many women, however, such a procedure would remove the trauma of losing their fertility before they reach the stage of wanting children.
Louise Lockley, 23, a business studies student from Dudley in the West Midlands, was diagnosed with ovarian cancer at age 19. She had her ovarian tissue removed and frozen before undergoing 14 cycles of chemotherapy.
"I was told about all the possible side effects of my treatment and fertility was my main concern." she said. "I thought I could handle the hair loss but my biggest fear was not being able to become a mum. After death, fertility was the next biggest worry."
Lockley decided to have her ovaries removed even though scientists have not yet achieved a successful pregnancy through ovarian transplants in humans. " gives me great hope," she said.
The development was announced on the opening day of the Annual Conference of American Society for Reproductive Medicine in Texas.
Researchers took ovarian tissue from seven monkeys of childbearing age. The tissue was transplanted into various body parts, including the kidney, stomach and arm. Scientists found estrogen and progesterone hormones were produced and follicles developed within the tissue.
They were able to extract eggs from these follicles. The scientists then used a fertility treatment called Intra-cytoplasmic sperm injection (ICSI), which involves injecting a single sperm into an egg, which is then transferred into the womb. All seven monkeys produced reproductive hormones and four had eggs removed. Of these, two underwent the fertility process, resulting in one successful birth; a healthy, 500g female.
Researchers will now work on how the process can be developed for treating infertility in humans. The work comes two years after French scientists successfully transplanted previously frozen ovaries into infertile sheep that then gave birth to healthy lambs. The work at a research centre in Lyon resulted in four successful pregnancies.