Scientists from Leeds University have developed a method of storing small sections of their ovaries, which contain immature eggs, and preserving them in "ovarian tissue banks". The doctors believe that within five to ten years they will have techniques to enable them either to mature the human eggs in the laboratory or replant the healthy tissue into the recovered cancer patients to allow natural conception.
At present, a woman with leukaemia having chemotherapy or radiotherapy is likely to be made infertile because there is no way of protecting her ovaries. But human eggs are so delicate they cannot be stored unless they are fertilised, as embryos. The new procedure means the sufferers need not be faced with a future childless relationship.
The scientists have stored the ovarian tissue of nearly 100 young patients. But cancer patients will not be the only beneficiaries, said Dr Helen Picton, of the centre for reproduction, growth and redevelopment at Leeds. "Women who have a family history of early menopause could benefit as well as those who want to delay having a family," she told the annual conference of the European Society of Human Reproduction and Embryology in Tours.
"It could be used as a `career pill', allowing women to bank their ovarian tissue before they reach the age of 30 and have their healthy eggs recovered when they are older."
But scientists are concerned that children born by this new method could experience premature ageing. Other research on animals is under way to test whether offspring born from eggs grown up in the laboratory have normal development.
"We have to ensure the safety of this procedure so any future child born through these techniques will have normal development," said Dr Picton.
Women are born with a bank of hundreds of thousands of immature eggs, which are expended during their lifetime. After 30 the number depletes rapidly and the menopause, a sign that all the eggs have gone, occurs for most women at around 50.
The scientists from Leeds have already managed to grow immature human eggs from ovarian tissue in the laboratory. In a study involving ovarian tissue of 20 women the scientists brought the eggs to a stage where they were ready to mature.
But they have not yet taken the eggs to full developmental maturation, which would allow proper fertilisation. The ovarian tissue was collected from women with an average age of 29, who were about to undergo Caesarean section or routine surgery. The immature eggs were grown in tissue culture and their development was assessed as "normal".