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Hope for non-invasive pregnancy test

4 March 2004
By BioNews
Appeared in BioNews 248

US researchers have developed a new method for testing fetal DNA, which does not involve the use of invasive techniques such as amniocentesis or CVS (chorionic villus sampling). The scientists, based at the biotech company Ravgen, have found a way to increase the amount of fetal DNA that can be extracted directly from the mother's blood. A commentary piece accompanying the study, which appears in the Journal of the American Medical Association (JAMA), says that the work could have 'profound clinical implications' for prenatal diagnosis and cancer screening.

Currently, tests for Down syndrome and genetic conditions such as cystic fibrosis rely on taking fetal cell samples, using either amniocentesis or CVS. Both techniques involve injecting a needle into the womb, and so carry a small risk of miscarriage. Because of this, researchers have been trying for some time to develop a non-invasive technique for carrying out genetic tests during pregnancy.

It was already known that a small number of cells from the fetus always find their way into the mother's bloodstream, where they are attacked by the maternal immune system. But although previous studies have shown that small amounts of the resulting 'free fetal DNA' can be detected in a sample of the mother's blood, it is usually swamped by large amounts of DNA from maternal white blood cells.

In the new study, the researchers treated blood samples from pregnant women with the chemical formaldehyde, which 'hardened' the maternal blood cells, stopping them from bursting and releasing their DNA. This boosted the relative amount of fetal DNA present, from around 7 per cent in the untreated samples to an average of 25 per cent in a follow-up study of 69 formaldehyde-treated samples. Over a quarter of the samples contained 50 per cent fetal DNA, prompting the authors to write that 'this lays a solid foundation for the development of a non-invasive prenatal diagnostic test'. The JAMA commentary piece adds that as well as prenatal tests, the technique could also potentially be used to detect cancer cells, and monitor their spread.

Alastair Kent, director of the UK's Genetic Interest Group, told BBC News Online that a non-invasive prenatal diagnosis technique would give pregnant women the opportunity to have information on which they could make decisions, 'without potentially putting the future of a healthy pregnancy at risk'.

Blood test may replace invasive procedures on moms-to-be
Chicago Sun Times |  3 March 2004
Hope for safer foetus gene tests
BBC News Online |  3 March 2004
Researchers eye alternative to amniocentesis: study
Yahoo Daily News |  3 March 2004
Test may be safer way to detect fetal problems
Reuters |  3 March 2004
6 February 2007 - by Dr Jess Buxton 
A new study offers 'proof of principle' for a non-invasive pregnancy test that can detect conditions such as Down syndrome using samples of the mother's blood. The findings, published online in the Lancet journal, show that the technique correctly diagnosed 58 out of 60 samples, with...
6 October 2005 - by BioNews 
Scientists based at Hong Kong University have found a way to identify traces of fetal DNA in a pregnant woman's blood, bringing non-invasive prenatal testing a step closer. The researchers, who published their findings in the Proceedings of the National Academy of Sciences, have developed a new technique for distinguishing...
14 July 2004 - by BioNews 
A new technique could provide an alternative to invasive pregnancy tests, researchers based in the US and Asia have shown. Using small amounts of fetal DNA present in the mother's blood, they have managed to carry out prenatal tests for the inherited blood disorder thalassaemia. The study appeared in the...
26 January 2004 - by BioNews 
Accurate prenatal tests for Down syndrome and other chromosome disorders should be made available to all pregnant women, not just those over 35, according to a new US study. Researchers at the University of California, San Francisco, evaluated the cost-effectiveness of invasive methods such as amniocentesis, and also surveyed 534...
22 October 2003 - by BioNews 
The UK's National Institute for Clinical Excellence (NICE) and the National Collaborating Centre for Women's and Children's Health have published recommendations for the National Health Service in England and Wales on the routine care of healthy pregnant women. The NICE guidance includes advice on how many antenatal appointments each woman...
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