Scientists from the University of Michigan Comprehensive Cancer Center said they have developed a method of freezing cells called vitrification, which stops the eggs from being damaged when they are thawed.

They said they would only offer the treatment to women facing chemotherapy or radiotherapy for cancer because the long-term safety remained unknown, reports the Scotsman.

Traditional methods of egg freezing have not worked well because the cells are too large and when the egg is thawed it is damaged by the ice crystals.

Vitrification allows the eggs to be cooled fast enough so that the transformation from liquid to solid is instantaneous, with no ice crystals formed.

The researchers have so far used the technique in mouse eggs but expect to use it in clinical trials shortly.

Researcher Gary Smith said: "With traditional slow-freeze techniques, just over half the eggs survive the thawing process. Using vitrification, we are getting 98 percent survival."

But for egg freezing to work, a mature egg must be used, meaning women have to have 14 days of hormone treatment to stimulate egg production.

This can delay the start of cancer treatment and may not be appropriate for women with cancers fuelled by oestrogen - such as breast cancer.

Prof Smith said: "In a woman with cancer, if she is going to lose her reproductive capacity because of cancer treatments, this is her only choice to have a baby with her own eggs."

Said Allan Pacey, the British Fertility Society secretary: "Women diagnosed with cancer have had a rough time when it comes to considering fertility issues before treatment.

"This technique, if it is going to work, is good news."

Pacey, from the University of Sheffield, said using traditional egg-freezing techniques, only around one in 100 women would go on to have a baby.

He said women still faced the issue of whether to delay cancer treatment in order to undergo the process necessary to freeze eggs.

"Some women may not feel able to delay treatment, and I can quite understand that. But for some women, especially those who are a lot younger, this is at least something they can consider," Pacey said.