Pregnancy could be delayed for cancer sufferers. Credit: © Getty Images

A cancer patient who had part of an ovary removed, frozen and then reimplanted after the disease had been treated, is now pregnant. The 32-year-old woman, who is expecting a baby girl in October, is the first to fall pregnant after such a procedure.

Scientists are hailing the announcement as a breakthrough for those left infertile by cancer treatment. But some are concerned that the technique could be used by healthy menopausal women who choose to delay motherhood for reasons of convenience.

The patient developed Hodgkin's lymphoma seven years ago, so doctors removed and froze samples of her ovarian tissue before beginning cancer treatment.

Last year, with the disease in remission, one sample was thawed and implanted below one of her remaining, non-functioning ovaries. She then became pregnant naturally. However, it has not yet been confirmed that the fertilised egg came from the graft. It is possible then that the woman's remaining ovary may have spontaneously started to work again.

Marie-Madeleine Dolmans, from the Catholic University of Louvain in Belgium, will discuss the research at the European Society for Human Reproduction and Embryology meeting in Berlin today.

Although the baby has yet to be born, this is still a landmark finding, says reproductive biologist Kutluk Oktay from Cornell University, New York, who has also been working towards storing and reimplanting ovarian tissue. "The technique could help give cancer patients a much more positive attitude," he says.

Defying menopause

Researchers have been trying for years to reimplant or transplant functioning ovaries. This week, fertility researcher Claus Yding Anderson from the Copenhagen University Hospital, Denmark, announced that his group had also produced an embryo after reimplanting ovarian tissue into another cancer patient. But the embryo failed to implant in the womb, for unknown reasons. "The new study is fantastic news," he says.

The development could have implications for people other than cancer patients. Women are born with around 1 million eggs, but those eggs die off as the menopause approaches. So, in theory, women could choose to preserve a sample of ovarian tissue and then reimplant it after their natural fertility had run out.

"It is too early to say if this will happen," says Oktay. "We do not know how efficient the process is." But if the success rate is 30% or more, similar to that of in vitro fertilization, then it is a possibility. "What's important is that women have the option to choose," he adds.