The fertility technique, called in vitro maturation (IVM), could be a good alternative to conventional IVF for some high-risk women, say experts.

Under the process, women do not first need to take potentially risky fertility drugs as they do with IVF.

The technique is also cheaper and faster - but its success rate is lower and it is not available on the NHS.

Doing well

The twins were delivered a minute apart on Thursday 18 October.

The boy was born first, weighing 6lb 11oz, while his sister weighed 5lb 14oz. Both were said to be doing well.

Their names have not been released by their parents, who wish to protect their privacy.

Under IVM, the mother gave birth to the twins using her own eggs matured in a laboratory

In January, the Oxford Fertility Centre was awarded the only licence in the UK to offer IVM.

The technique is still relatively new - about 400 IVM babies have been born globally, compared to 2 million IVF babies.

This is good news. There is always a need for alternative ways of doing things

Dr Richard Fleming, of the British Fertility Society

For standard IVF treatment, a woman needs to take drugs to shut down her ovaries and then undergo two weeks of daily hormone injections so that mature eggs can be retrieved from her ovaries.

With IVM the woman needs only one injection. The immature eggs are retrieved from a woman's unstimulated ovaries under ultrasound guidance and then matured in the laboratory for 1-2 days.

Some women develop a potentially fatal reaction to the powerful drugs needed for normal cycles of IVF.

With both treatments, once the eggs are fertilised in the lab the resulting embryos are transferred to the woman's womb.

Tim Child, consultant gynaecologist at the Oxford Fertility Clinic says IVM has clear benefits over IVF for some women, particularly those with polycystic ovarian syndrome.

Not only does it reduce inconvenience and discomfort, it also removes the risk of a condition called ovarian hyperstimulation syndrome (OHSS).

In mild and moderate cases, affecting up to 20% of women undergoing ovary stimulation, this leads to symptoms such as swelling and breathlessness that resolves.

However, in about 1% the symptoms can become so severe that they are deadly. Among women with PCOS, the rate is nearer 5-10%.

Expense

IVM treatment is also shorter and less expensive than IVF.

On the flip-side, the success rates are lower, however.

Mr Child said: "IVF, overall, has a better success rate, but the side effects are higher.

"Patients should have the choice of an alternative. IVM is safer, simpler, cheaper and more acceptable."

Some have expressed theoretical concerns that the maturation process could somehow damage the eggs and lead to abnormalities in any resulting babies.

This has not been borne out by the IVM births to date, although experts say they will continue to scrutinise the safety of this new treatment.

Mr Child said the twins, who were born 18 October, were both doing well.

Dr Richard Fleming, of the Glasgow Centre for Reproductive Medicine and the British Fertility Society, said: "This is good news. There is always a need for alternative ways of doing things."

He said women should be counselled about the pros and cons of both treatments.

A spokeswoman for the Human Fertilisation and Embryology Authority said the organisation would be closely tracking the use and outcomes of IVM.