A new technique for screening embryos that will dramatically improve the chances of older women having babies was unveiled by scientists yesterday.

A 42-year-old woman has become pregnant after being screened using the new IVF technology, which can identify abnormalities within a single cell. The finding will bring hope to a growing number of women over the age of 35 who are facing fertility problems after putting motherhood on hold.

Younger women who want to avoid the risk of miscarriage or a child with Down syndrome will also be able to benefit from the technique, known as aneuploidy screening, which focuses on identifying chromosomal abnormalities in embryos.

The screening, which is licensed by the Human Fertilisation and Embryology Authority (HFEA) is currently available in Britain only for women over the age of 35, or for those who have a history of miscarriages and failed IVF treatment. The Care clinic at the Park Hospital in Nottingham, which was the first in the country to obtain a licence for the treatment last November, yesterday announced that the 42-year-old woman was expecting a child as a result of the new technology.

The pregnancy was hailed as a landmark case as she was over the age of 40, had endured numerous miscarriages and was suffering from long-term fertility problems.

About 30 more women are hoping to conceive the same way and have requested the new treatment, according to the head of the clinic, Dr Simon Fishel.

"There are a lot who are interested," he said. "There are those who have come off the IVF roundabout because they were told three to four years ago that there was not much more that could be done for them and would now at least like an answer."

With two further clinics being granted licences to carry out the screening procedure, reproductive ethics groups accused scientists of paving the way for the creation of a generation of so-called designer babies.

Josephine Quintaville, the director of the campaign group Comment on Reproductive Ethics, said: "We have to find a solution that does not involve getting rid of unborn children."

However, Dr Fishel rejected accusations that screening for abnormalities was equivalent to creating designer babies.

"This is screening before the pregnancy is even established. It is selecting out the negative," he said.