When you are expecting, there are undoubtedly a multitude of things on your mind, and of course the most prevalent will be the health of your unborn child. While there are indeed some women who don’t opt for prenatal screening, many consider having an awareness of any possible foetal abnormalities to be completely essential, particularly if they are aged 35 or over when these are more common.
Unfortunately the traditional screening method, the Nuchal Translucency or 12 Week Scan, leaves room for doubt (it detects only 90% of Down’s fetuses). Some women will opt for more accurate tests, such as chorion villous sampling (CVS) or amniocentesis, however these invasive procedures have a 1 in 100 risk of miscarriage.
A simply blood test is now available that could save the lives of hundreds of babies every year
Luckily, thanks to cutting-edge research from Kings College London, a simple blood test is now available that could save the lives of hundreds of babies every year. Developed by American firm Ariosa Diagnostics, the Harmony Test has been extensively screened and praised.
The Harmony Test screens for Down’s syndrome and other more unusual chromosomal abnormalities such as Edwards syndrome and Patau syndrome. As opposed to more traditional testing methods, the Harmony Test is more accurate and less invasive.
In the past, doctors have screened for Down’s syndrome and other chromosomal abnormalities using Nuchal Translucency Scanning at about 12 weeks, which analyses the skin fold on the back of the fetus’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 offer about a 90% certainty rate in terms of the results, which leaves a relatively high margin of error.
The Harmony Test carries no risk to the baby (or the mother)
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.
Alternatively, the Harmony Test is safer and much more reliable as it scrutinises the baby’s cell free DNA. It detects 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.
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. 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.
After you take the Harmony Test, you must wait 10 days for the results which are concluded in the US. You will then undergo a 12 week scan, and 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.
It is important to note that if the Harmony Test is negative, then it is necessary that the sonographer is aware of that. If the test is positive, you should consider seeking counselling, which may be available either on the NHS or through a private clinic.
The Harmony Test costs around £600 and this fee typically includes an ultrasound scan. The Harmony Test is not currently available on the NHS but there is hope that this vastly improved foetal testing for genetic abnormalities will one day be available to all.
Professor Nicolaides from The Fetal Medicine Centre will be discussing Non-Invasive Prenatal Testing (NIPT) and The Harmony Test in his seminar (12pm, Sat 21 May) at the Private Pregnancy UK Show at the Royal Institution, London. privatepregnancy.co.uk
Down’s Syndrome Awareness Week runs from 20-26th March 2016. Find out more here.
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