Screening 'halves number of Down's syndrome babies'
Friday, 28 Nov 2008 08:10
Results from national screening strategy in Denmark see number of children born with Down's syndrome halved
Initial results from a national screening strategy in Denmark have seen the number of children being born with Down's syndrome halved.
The strategy, introduced four years ago, has also led to a 30 per cent increase in the number of successful diagnoses.
Denmark approved the national rollout of a combined test – based on maternal age, plus serum and nuchal screening in the first trimester - for Down's syndrome in 2004, whereas other countries including the UK have struggled to find a consensus about the screening policy and logistical challenges.
This test gave women a risk assessment for Down's syndrome at an early stage in the pregnancy. Women whose risk was higher than a defined cut off were referred for invasive diagnostic tests (chorionic villus sampling or amniocentesis).
In the previous guidelines screening for Down's syndrome was based on maternal age and a diagnostic test was mainly offered to women above 35 years.
Professor Ann Tabor and colleagues from Denmark, publishing their results in the British Medical Journal (BMJ) evaluated the impact of the new national screening strategy on the number of infants born with Down's syndrome and the number of referrals for invasive procedures.
Analysis of 65,000 births every year between 2000 and 2007 found that by 2006 eight out of ten pregnant women underwent the risk assessment for Down's syndrome.
As well as a 50 per cent cut in invasive tests by 2005 and 2006 31 and 32 cases of Down's syndrome were reported respectively, compared to 55-65 per year during 2000-4.
"The value of this new screening strategy is that all women can be assessed early in pregnancy (in the first trimester)," the report authors write.
"The national guidelines emphasise that risk assessment should only be done if women choose the test on the basis of informed choice, therefore despite the programme being available to all pregnant in women in Denmark, some will still choose not to be screened."