Blood screen less threat to foetus Joy: Kylie Dunstan with Chloe and Lachlan. Australian women are risking miscarriage with invasive Down syndrome tests because a new, safer and more reliable blood test has not been made available. The cfDNA test, which analyses a baby's DNA from a mother's blood, is available in the US, and some Australian mothers are opting to spend between $1000 to $1200 to send their blood samples overseas to access it. The DNA is screened for chromosomal disorders - known as trisomies The test can more reliably detect whether an unborn baby has Down syndrome during the first trimester and does not carry a risk of miscarriage, unlike chorionic villus sampling and amniocentesis - the two tests used by doctors across the nation. Associate professor of obstetrics and gynaecology at the Australian National University Steve Robson said the test should be made available to all women shown to have a high probability of carrying a Down syndrome child after the nuchal translucency test. According to a study by the Harris Birthright Centre at King's College, London, the combined ultrasound and blood tests usually carried out between the 11th and 13th weeks of pregnancy return false positive results in 3.5 per cent of cases, while the cfDNA test returns false positive rates of 0.1 per cent. The study also found that when carried out after combined testing, 98 per cent of cases of Down syndrome could be detected and invasive testing was only needed for confirmation in 0.5 per cent of cases. Since February, Dr Robson has had about 20 patients send their blood to the US for testing. From six or seven weeks of pregnancy about 5 or 6 per cent of all free DNA fragments in a woman's blood come from the baby. Having a needle put in to the pregnancy to analyse the same result carries a risk of miscarriage. As a general rule the risk of having amniocentesis to a healthy baby is probably one chance in 150. It may sound like a small chance but over the years I've had a couple of miscarriages [as a result of amniocentesis] and it's an absolutely devastating situation. A spokesman from the Health Department said the test could be subsidised under Medicare but no applications to bring the test to Australia had been received. Dr Robson said subsidising the test in Australia would give women piece of mind. That is the real role of this test - have the NT test and if that result is not reassuring then rather than having an invasive test, put that aside and look at having the DNA test done. Kylie Dunstan and her husband made the difficult decision to have two amniocentesis tests performed despite a one-in-150 chance of the invasive tests causing their unborn babies to die. Earlier tests showed the twins had a one-in-three chance of Down syndrome and chromosomal abnormalities not compatible with life. "When I found out it was twins and the risk factors associated with an amnio - you start thinking of the numbers and it becomes more real," she said. " You have a totally different response to it. Chloe and Lachlan were born eight months ago after the amniocentesis showed no chromosomal abnormalities. But the wait and stress of the tests took their toll. If the cfDNA test had been available, the couple would have taken up the option: "Regardless of the cost ... absolutely."