Evidence suggests women's ovaries can grow new eggs.

Scientists have uncovered the first evidence that the human ovary may be able to grow new eggs in adulthood. If confirmed, the discovery would overturn the accepted view that women are born with a fixed number of eggs and that the body has no capacity to increase this supply. Until now this has been the main constraint on the female reproductive lifespan. The findings, if replicated, would raise the prospect of new treatments to allow older women to conceive and for infertility problems in younger women. The small study, involving cancer patients, showed that ovarian biopsies taken from young women who had been given a chemotherapy drug had a far higher density of eggs than healthy women of the same age. Woman gives birth after pioneering ovarian tissue transplant Read more Prof Evelyn Telfer, who led the work at the University of Edinburgh, said: “This was something remarkable and completely unexpected for us. The tissue appeared to have formed new eggs. The dogma is that the human ovary has a fixed population of eggs and that no new eggs form throughout life.” Her team initially set out to investigate why the drug, called ABVD, does not cause fertility problems, unlike many forms of chemotherapy. Although the research is promising, Telfer warned against the apparent eagerness of some fertility clinics to offer novel treatments before the basic science is well understood. “There’s so much we don’t know about the ovary,” she said. “We have to be very cautious about jumping to clinical applications.” The findings have been greeted with a mixture of excitement and scepticism. “I think that these findings, and the identification of the mechanisms involved, may pave the way for development of new fertility treatments or extend women’s reproductive span by replenishment of the ovaries with new follicles,” said Kenny Rodriguez-Wallberg, a senior consultant at the Karolinska University Hospital in Stockholm. “It suggests that the ovary is indeed a more complex and versatile organ than we have been taught, or that we expected, with an inherent capacity of renewal.”

Breakthrough as human eggs developed in the lab for first time.

Women at risk of premature fertility loss might have cause for new hope as researchers reveal that human eggs can be developed in the lab from their earliest stages to maturity. While the feat has previously been achieved for mouse eggs, and has given rise to live young after fertilisation, the process has proved tricky in humans. Experts say the latest development could not only aid the understanding of how human eggs develop, but open the door to a new approach to fertility preservation for women at risk of premature fertility loss – such as those undergoing chemotherapy or radiotherapy.