Blood test for Down's 'could save 300 babies' lives a year'

Expecting mother holding her belly, only two weeks to go!

September 04 2012 09:45 AM

A NEW blood test that checks all pregnant women for signs of Down’s syndrome in their unborn children could be available on the NHS in the UK by 2017, say scientists, potentially saving the lives of 300 babies every year.

At the moment some 30,000 women every year, who are deemed at high risk of carrying a Down’s baby, face the dilemma of whether or not to undergo a very invasive test that carries a 1 in 100 chance of causing a miscarriage.

But today UK-based scientists report results from a trial of the new blood test in 2,049 women, showing that it is more than 99 per cent accurate and suitable for mass screening.

Professor Kypros Nicolaides, of the Harris Birthright Research Centre for Foetal Medicine at King’s College Hospital in London, said last night: “This test is highly accurate for routine screening of all pregnant women, not just those deemed high risk.

“My expectation is that it will be adopted by the NHS in five years.”

Trial results are published today in the American Journal of Obstetrics and Gynaecology.

Currently the NHS uses a two-stage process to check for Down’s. Firstly, all foetuses are screened to see if they are at a high or low risk of the genetic disorder at the 12 week ultrasound scan, called the ‘nuchal translucency test’.

For every 10,000 pregnant women, some 527 are then advised as result of this ultrasound test to have the invasive second-stage test.

Prof Nicolaides, who himself worked on development of the nuchal test, said the blood test would cut the number needing the invasive procedure to just 10 in 10,000.

The blood test would also pick up more cases of Down’s than the combined two-stage process, he said.

“For every 10,000 women, 30 carry foetuses with Downs,” he explained.

“The current process picks up 27 but miss the other three. With the new test, we will pick up all 30.”

It therefore has the potential to all but eradicate Down’s syndrome, which is caused by an extra copy of chromosome 21, and affects about 750 babies a year.

The Harmony Prenatal Test, as it is called, is being developed by Ariosa Diagnostics, a US firm. In Britain, research has been supported by The Foetal Medicine Foundation, a charity.

Prof Nicolaides said that he would “within weeks” be making the test available for free to women in Britain who agreed to be part of the ongoing trial.

He said it took him 12 years to convince the NHS to adopt nuchal translucency screening, with results from “hundreds of thousands” of women needed.

However, he said: “I think they will move faster with this.”

Gynaecologists regard a non-invasive test for Down’s as “the holy grail”, as they know how many women agonise over the decision to have the current second-stage test.

A Department for Health spokesman said: "The UK National Screening Committee will keep all evidence for pre-natal screening under review and make recommendations in light of any new findings."

Stephen Adams Telegraph.co.uk