A non-invasive prenatal test (NIPT) is an advanced screening test using DNA in the mother's blood to estimate the risk of a fetus having Down’s syndrome, Edwards' syndrome and Patau’s syndrome. There are many different NIPTs on the market, but the majority will screen for these three syndromes. Edwards’ and Patau’s syndrome are much rarer than Down’s syndrome but are very serious and many affected babies die before or soon after birth. Trisomies occur when three, instead of the usual two, copies of a chromosome are present.
Traditional screening offered during the first trimester of pregnancy is currently called the combined test. This is an ultrasound scan to measure the nuchal translucency (NT), combined with a blood test. This is less accurate than NIPT, detecting about 85% of babies with Down’s syndrome. The IONA® test has a higher detection rate than the combined test. The IONA® test is also able to better exclude false positives. This is when the test says the baby is at a high risk of having Down’s syndrome but is actually unaffected. The IONA® test is much better at ensuring the babies are truly high risk. This allows the doctor to only refer the mother for an invasive test when it is likely the baby is affected. This means fewer pregnant women will undergo unnecessary invasive follow-up procedure such as amniocentesis or CVS which can be stressful, painful and may carry a small risk of miscarriage.