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The Harmony Prenatal DNA Test –
Non-invasive Screening For Down Syndrome

Video: The Harmony Prenatal Test
(Click image to play)

As a mum-to-be, you’ll be no stranger to worries about the health of your unborn child. While there are indeed some women who don’t opt for prenatal screening, many couples consider it essential to have an awareness of any possible foetal abnormalities they may be facing, in order to best prepare for any trying times ahead.

However the traditional screening method, the Nuchal Translucency or 12 Week Scan can leave some room for doubt (it has a predictive value of 92%). Some women will proceed to more accurate tests, such as chorion villous sampling (CVS) or amniocentesis, however these invasive procedures have a 1 in 100 risk of miscarriage.

Now thanks to expert research conducted by doctors at Kings College London, a simple blood test is available that could save the lives of hundreds of babies every year. The Harmony test was developed by American firm Ariosa Diagnostics. It has been extensively screened and given the thumbs up by a leader in the field of foetal medicine, the specialist that developed nuchal fold testing, Dr Kypros Nicolaides.

A simple test is available that analyses a blood sample

What is the Harmony test?
The Harmony test screens for Down’s syndrome and other more unusual chromosomal abnormalities such as Edwards syndrome and Patau syndrome.

Down syndrome can create moderate to severe learning disabilities. The condition is also linked to compromised vision and hearing, as well as heart problems.

Edwards syndrome and Patau syndrome are associated with high miscarriage rates. Babies with either of these syndromes are born with severe brain defects and further birth defects, and often suffer from congenital heart conditions. Most affected babies die either before or soon after birth. Very few will survive past their first year of life.

Why is the Harmony test preferable to traditional testing methods?
For the last decade, doctors have been screening for Down syndrome and other chromosomal abnormalities using Nuchal Translucency Scanning at about 12 weeks, which analyses the skin fold on the back of the foetus’s neck. The nose bone of the baby is also examined, and blood is taken from the mother to look for two pregnancy hormones. This is known as the Combined Test. It can offerThe Hamony test has a predictive value of over 99% for Down syndrome about a 92-93% certainty rate in terms of the results, which is obviously a relatively high margin of error. Women who receive ‘high risk of abnormality’ results are given the option to undergo chorionic villous sampling (CVS) or amniocentesis. These tests are invasive, involving needle insertion into the womb – and around 1 in 100 of them will result in miscarriage.

The Harmony Test is safer and much more reliable.
The Harmony Test scrutinises the baby’s cell free DNA. Its predictive value is over 99% for Down’s syndrome, and slightly less for Edwards syndrome (98%) and Patau syndrome (80%). This is a significant accuracy improvement on earlier methods.

TrisomyDetection RateFalse Positive Rate
Trisomy 21
(Down syndrome)
>99%<0.1%
Trisomy 18
(Edwards syndrome)
>98%<0.1%
Trisomy 13
(Patau syndrome)
8/10<0.1%

Obviously the only way to be 100% sure that your baby is free from chromosomal abnormalities is to undergo amniocentesis or CVS testing, however the Harmony test leaves you as sure as you can be without risking miscarriage.

A good result narrows the chances of Down syndrome to under 1 in 10,000. A bad result indicates a very high risk of the condition but a good doctor will interpret the findings along with a scan result and the overall clinical situation.

Unlike amniocentesis and CVS testing, the Harmony test carries no risk to the baby (or the mother). Blood will simply be taken from a vein in your arm.

This accuracy improvement can save the lives of hundreds of little ones each year.

The false positive result for the traditional Combined Test is generally about 4.5%. This means that around 45 women in 1000 undergo unnecessary invasive testing each year – and the stakes are high. About 300 babies are lost in the process of amnio and CVS testing every year; a significant number of them healthy. Furthermore, the accuracy rate of only 92-93% for Combined Testing means that many cases of chromosomal abnormality are not detected at all, creating a shock for Mum and Dad at birth.

In what cases should I seek a Harmony test?
It is up to you. The Harmony test can be conducted following a 10 weeks Viability Scan, or in addition to the 12 weeks Combined Test if indications of abnormality are detected.

Are there foetal problems that the Harmony test will not uncover?
Yes. Structural problems such as Spina Bifida and heart defects can only be identified through scanning, and often not until later on in your pregnancy. Routine scans, for example your 20 Week Anomaly Scan, must still be performed.

Things to remember if you are having a Harmony test
It is important to have an ultrasound before your blood test in order to confirm you have a living pregnancy and that it’s not twins or a multiple pregnancy. This is because a Harmony test is unable to check individuals, so you will need to rely on traditional screening in this instance. The same is true if you are pregnant through egg donation.

How long will I have to wait for my results to come through?
Two weeks. Your sample will need to be sent to the USA for analysis.

What happens after I’ve taken the Harmony Test?
If you are 10-12 weeks pregnant when you take the Harmony test you will still be able to have a 12 week scan, either privately or with the NHS. However, there will now be a different focus to the test.

Since you will already have the results of the Down’s syndrome, Edwards syndrome and Patau syndrome test, this scan will focus on analysing the baby in a detailed way to look for structural abnormalities (these can obviously be present without a chromosomal abnormality). If the Harmony Test is negative then it is important that the sonographer is aware of that.

If the test is positive then you should consider seeking counselling, which may be available either on the NHS or through a private clinic.

How much does a Harmony Test cost?
The Harmony Test costs around £600 – £650. The fee usually includes an ultrasound scan.

Where can I take the Harmony Test?
The Harmony Test is not currently available on the NHS, and is unlikely to be for some time.

You can find a list of private clinics in the UK which offer the Harmony Test here.

The Harmony Prenatal Test Brochures


The Harmony Test Patient Information Brochure


The Harmony Test Brochure with Clinical Data Summary

Related Pregnancy Scan: 12 Week Scan – Nuchal Translucency Scan

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