Sunday, September 14, 2008
Down's tests are great risk for all babies Screening for syndrome puts healthy foetuses in danger of being miscarried, new research shows
and was published in The Observer, Sunday September 14 2008
Down's tests are great risk for all babiesScreening for syndrome puts healthy foetuses in danger of being miscarried, new research shows
Victoria Macdonald The Observer, Sunday September 14 2008 Article historyRisks in screening unborn babies for Down's syndrome are far higher than previously claimed, new research will say this week. For every three unborn Down's syndrome babies prevented from being born, two healthy babies will be miscarried because of the methods used to detect the condition.
The research claims that, in detecting and preventing the birth of 660 Down's babies, 400 healthy foetuses are lost.
The research casts doubt on the advice and risk assessment given to women when they are deciding whether to undergo the screening and subsequent testing to assess the health of an unborn baby. The National Health Service currently cites a miscarriage rate of between 1 and 2 per cent following the invasive amniocentesis and chorionic villus sampling (CVS) tests, which are offered to expectant mothers who are considered to be 'at risk'.
The authors of the paper - which is being published in the Down's Syndrome Research and Practice journal - say that, while the number of pregnancies diagnosed with Down's syndrome that are terminated, miscarried or born are recorded, no analysis has ever been attempted to determine the number of non-Down's babies lost.
The authors are from the charity Down's Syndrome Education International and might therefore be accused of pursuing their own agenda, but the research has been shown to a number of screening experts who have assessed the findings. In a film to be screened on Channel 4 News at 7pm on Tuesday, Professor Kypros Nicolaides, head of the Harris Birthright Centre at King's College Hospital in south London, will say it is 'completely unacceptable' to lose this number of normal babies.
'Our aim must be to improve the detection of foetuses with Down's in those women that want to have a test and dramatically reduce the number of normal babies that are lost as part of this process of screening,' said Nicolaides, who has been a pioneer in the use of ultrasound for improving screening.
The authors of the study - Frank Buckley and Professor Sue Buckley, a director of the charity who also works at Portsmouth University's psychology department - blame false screening results in the initial blood testing and then the use of subsequent testing, which involves inserting a fine needle through the woman's abdomen and either withdrawing amniotic fluid or taking a tissue sample.
To detect as many Down's babies as possible, the initial screening threshold is set wide, which means that more than 95 per cent of women defined as 'high risk' will not be carrying a baby with the disorder, yet most go on to have the amniocentesis or CVS tests.
The Buckleys and Nicolaides are particularly concerned about how well qualified the staff are who carry out the invasive testing and about their ability to use ultrasound. Studies in the past have shown that loss rates following amniocentesis are six to eight times higher among inexperienced practitioners.
Because no records of non-Down's baby losses have ever been kept, the Buckleys say that their ratio of three to two can only ever be an estimate. But their methodology appears to have been broadly accepted.
'We are looking at the wider question of public health policy,' said the Buckleys. 'The screening for Down's syndrome has consequences for every pregnant woman. You cannot look at it as just a search-and-destroy mission focused on babies with Down's alone.'
About 750 Down's babies are born every year in England and Wales and the Department of Health said the primary aim of screening for the syndrome was to help women make informed decisions about their pregnancies. A spokesman said the programme was based on the latest evidence and supported the most effective test in terms of both the detection rate and the aim of lowering the screen-positive rate 'in order to minimise the number of diagnostic tests'.
The National Institute for Health and Clinical Evidence has recommended a new 'combined screen', which is meant to be more effective in assessing who is at risk, but this has yet to be rolled out nationally.
The Down's charity has now written to the government asking for a thorough reappraisal of the 'purpose, performance and safety' of the screening programme.
· Victoria Macdonald is social affairs correspondent for Channel 4 News.
THE SAD THING ABOUT THIS... I KNOW THERE IS SUCH A LONG WAITING LIST IN THE US FOR ADOPTING KIDS WITH DS. I WOULD LOVE TO SOMEDAY ADOPT ONE- DON'T KNOW IF IT WILL EVER BE RIGHT FOR OUR FAMILY- BUT, IF THEY ONLY THOUGHT ABOUT CARRYING THE BABY TO TERM AND ADOPTING THEM OUT. AND ALL THOSE BABIES LOST TO INCONCLUSIVE TESTS!!!! WHAT A SHAME!!!