video transcript

Down's Syndrome is the most common chromosome abnormality in humans - and testing for it can be dangerous for expectant mothers. But now, in the UK, a new and painless blood test is offering improved Down's detection rates - without the risk of miscarriage. Currently, women carrying carrying a foetus deemed at high risk of developing the condition undergo an uncomfortable test called amniocentesis in which a needle is inserted into the womb. One in 100 women who have the test will miscarry. Professor Kypros Nicolaides led the study at London's King's College Hospital and says the Harmony Prenatal Test offers better security and less risk. SOUNDBITE (English) KYPROS NICOLAIDES, PROFESSOR OF FOETAL MEDICINE AT KING'S COLLEGE LONDON AND LEAD AUTHOR OF STUDY, SAYING: "The problem with the current situation is that a high proportion of women that carry a normal baby are subjected to an unnecessary, invasive test, and also about ten percent of the pregnancies that carry a Down's baby are not picked up by our current method of screening." Also known as trisomy 21, the condition is caused by the presence of a third copy of chromosome 21. The Harmony test looks for the extra chromosome in the mother's blood. SOUNDBITE (English) KYPROS NICOLAIDES, PROFESSOR OF FOETAL MEDICINE AT KING'S COLLEGE LONDON AND LEAD AUTHOR OF STUDY, SAYING: "We have now learnt that firstly we can now identify more than 99 percent of the pregnancies with a problem and we only need to do an invasive test in one in a thousand pregnancies, which is a big difference from what we are currently doing which is 50 in a thousand." The study screened more than 2000 women who were between 11 and 13 weeks pregnant. Nicolaides says the false positive rate - where tests produced erroneous results - was just 0.1 percent. Down's Syndrome is typically associated with a delay in cognitive ability and physical growth, and a particular set of facial characteristics. The World Health Organisation says Down's Syndrome babies account for around one in 1100 live births world-wide. The Harmony test, developed by Ariosa Diagnostics, is expected to become available in the UK within weeks.