More about the Harmony test
Posted on 24 June 2014
The Harmony test is the latest in prenatal screening tests and is available at the Panorama Fetal Medicine Centre. Dr Linnie Muller, who is recognised as one of South Africa’s leading experts in fetal medicine and fetal echocardiography, explains what it’s about.
What is the Harmony test?
A blood sample is taken from the mother and analysed for cell-free fetal DNA, which is essentially a marker in the mother’s blood of the baby’s DNA. The result of this simple blood test, taken at 10 weeks or later, can predict more than 99% in Down’s syndrome, 98% of Edward’s syndrome and 80% of Patau’s syndrome, which will largely reduce the need for invasive testing by chorionic villus sampling (CVS) or amniocentesis.
This is great news because it eliminates the risk (about 1:100) of miscarriage that can be caused by invasive testing through CVS or amniocentesis. It’s important that an ultrasound scan is performed just before the blood test to confirm the pregnancy, and to check whether the mother is carrying twins or more.
Why the Harmony test?
This is one of the most accurate non-invasive tests to predict the chance of a chromosomal abnormality in a pregnancy (greater than 99% accuracy for Down’s Syndrome). For the last 10 years we’ve been using the results of the nuchal translucency scan to advise pregnant women and their partners on their risk of having a baby with Down’s syndrome or other abnormalities. The nuchal translucency scan looks at the skin fold on the back of the baby’s neck at about 12 weeks, which has been further refined by looking at the nose bone of the baby with an additional blood test to identify two pregnancy hormones. This is the combined test and has achieved a predictive value of about 92% accuracy. Women with a high risk have an option to proceed to CVS or amniocentesis.
Who needs the Harmony test?
It’s available to anyone who wants extra reassurance about the normality of their pregnancy. Women who may need it are usually those who are anxious about their baby having a chromosomal abnormality such as Down’s, Edward’s or Patau’s syndrome, older women (particularly over 40), as well as those who’ve previously had a chromosomally abnormal pregnancy. It’s also helpful for those who have had a previous sex chromosome abnormality such as Turner’s syndrome.
Although having a baby at a later age may put you at a higher risk for complications, many older women have healthy babies. Once you know about the potential risks, you can turn your focus on all the things that go with a healthy pregnancy at any age – proper nutrition and diet, good prenatal care and preparation both emotionally and financially for your baby and the care that will be needed.
For more information, visit Fetal Medicine.
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The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.