Test for Down's syndrome gives hope to parents

The new screening method is used to detect Down’s syndrome and can also pick up Patau’s and Edwards’ syndromes and the move would mean far fewer women needing invasive amniocentesis tests, which carry a one per cent chance of miscarriage and about a one in 1,000 risk of serious infection.

At present, all pregnant women in England are offered a combined blood and ultrasound test when they are 10 to 14 weeks pregnant to check for abnormalities.

In new recommendations, government advisers said women found to have a one in 150 chance or greater of having a baby with Down’s, Patau’s or Edwards’ syndrome in the combined test should then be offered the non-invasive prenatal testing (NIPT).

Dr Anne Mackie, director of screening at Public Health England, said: “While the evidence suggests that NIPT is much more accurate in predicting Down’s syndrome than current tests, there are a number of questions about its use in a real-life screening programme that the evidence hasn’t yet been able to clarify.

“We don’t know how good the test is for other genetic conditions – Edwards’ and Patau’s syndromes – that are currently part of the programme, and the evidence review also found that up to 13 per cent of the NIPTs carried out didn’t give any result at all.

“The intention, therefore, is to monitor and evaluate as we go. That means rolling out the test across England in such a way that allows us to learn from the experience and alter the screening programme if necessary in light of any real-life findings. This will allow us to improve the information we can give women when they are offered the screening and help them make the right choice.”

The new screening method works on the knowledge that a developing foetus’s DNA circulates in the mother’s blood. This means some aspects of the baby’s genetic profile can be screened directly from the mother’s blood sample, and NIPT can be followed by an amniocentesis test if there is still any doubt on a diagnosis.

Ministers have yet to approve the recommendations from the UK National Screening Committee, but it is hoped rollout of the test could begin soon.

Studies have shown NIPT to be 99 per cent accurate in detecting Down’s. Researchers at Great Ormond Street Hospital in London published results last year showing the test was safe, 99 per cent accurate, and led to a greater number of parents taking the test.

As part of a trial carried out at GOSH, women at high and medium risk of having a child with Down’s syndrome were offered NIPT, with more than 2,500 accepting.

The vice-president of clinical quality for the Royal College of Obstetricians and Gynaecologists, Prof Alan Cameron, said: “This test is the most accurate and safest way of detecting diseases that may have potentially serious consequences, both enhancing the information available to pregnant women and reducing unnecessary invasive procedures.”