ABOUT THE ASTER BABY SCAN CLINIC
The Harmony™ Prenatal Test
Available from 10 weeks of pregnancy
When a woman is pregnant some of the baby’s cells (fetal DNA) enters her blood stream. These fetal cells are detectable during pregnancy and cleared from the blood after delivery. The Harmony™ Prenatal Test assesses the fetal DNA from a simple blood test from the mother and provides a risk for the three most common chromosome disorders, Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13).
The cells in our bodies contain genetic material (DNA) that determine how we are made up. The DNA is stored in structures called chromosomes. We have 46 chromosomes (that’s 23 pairs). If an error occurs this can lead to a problem with the chromosomes.
Down syndrome is due to an extra copy of chromosome 21 and is associated with some physical and learning disabilities. Edwards syndrome is due to an extra copy of chromosome 18. Patau syndrome is due to an extra copy of chromosome 13.
Edwards syndrome and Patau’s syndrome are associated with severe medical problems and affected babies may not survive pregnancy or die soon after birth.
Whilst every pregnancy has a chance of being affected by a chromosome condition, the risk increases with the age of the mother. The current national screening tests will detect around 70-80% of pregnancies with Down syndrome.
The Harmony™Prenatal Test will detect over 99% of fetuses with Down’s syndrome, 97% of fetuses with Edwards syndrome, and 92% of fetuses Patau’s syndrome.
Harmony™ Prenatal Test has a false positive rate of less than 0.1% compared to 5% with conventional screening, so fewer women will be told that they have a high risk when they do not have a high risk.
Overall this means that the Harmony™ Prenatal Test detects more pregnancies with Down syndrome but also reduces the risk of unnecessary invasive diagnostic procedures (chorionic villus sampling or amniocentesis).
The Harmony™ Prenatal Test is done from 10 weeks of pregnancy and involves a simple blood test from the mother.
It will also accurately identify the baby’s gender, but this will not be disclosed if you do not wish to know.
Who can have the Harmony™ Prenatal Test?
✓ If you are pregnant and wishes to have screening
✓ If you Twin pregnancies
✓ IVF pregnancies including self and non-self donor pregnancies
✓ If you missed your combined or quadruple test
✓ If you had a positive combined or quadruple test result and would like more information while you are making up your mind about undertaking an invasive procedure.
It is important to note that the The Harmony™ Prenatal Test does not replace diagnostic tests such as amniocentesis and chorionic villus sample as those tests are 100% detection. You would still have to consider these to exclude a chromosomal condition.
Are there situations where the test cannot be used?
The Harmony™ Prenatal Test cannot be used in a multiple pregnancy if one twin stopped developing at an early stage (a vanishing twin). We would recommend a scan to exclude this in a multiple pregnancy.
The mother has an unusual chromosome rearrangement
When do the results come back?
The results take around 5 working days to come back. We will inform you of the results by telephone as soon as they are available or face to face if you come for a scan at 12 weeks.
We can see you for face to face counselling if you require more information to help you understand the test and the implications of the result.
Who will analyse the Harmony™ Prenatal Test?
We send the blood test with in addition with your consent form to TDL Genetics Limited who will process the sample. The company will comply to confidentiality standards.
What will the results show?
The result may show a low or high risk result. A low risk means it is unlikely that the baby has Downs syndrome, Edwards Syndrome or Patau’s syndrome. Any screening has a risk of a ‘false negative’ or being told the risk is low when it is high. However the risk of this happening with the Harmony™ Prenatal Test™is much lower than with conventional Down screening A high risk result would means that a chorionic villus sample or amniocentesis would be the only way to find out if the baby has Downs syndrome, Edwards syndrome or Patau’s syndrome. A high risk result does not mean that the baby definitely has one of these conditions.
Sometimes a repeat rest will be required. This happens in around 3 out of 100 women. You will not be charged for a repeat sample.
Do I need to have any other tests?
The Harmony™ Prenatal Test™ does not provide information on other rare chromosomal abnormalities. If structural abnormalities are found at a later stage of pregnancy the risk for chromosomal abnormality will need to be reviewed as it may be higher.
We always recommend having an ultrasound scans at 11-13 weeks and at 20-22 weeks to examine the fetal anatomy.