Your questions answered about Non-Invasive Prenatal Test (NIPT) Scans
When you’re pregnant you just want to know that your baby is going to be okay. The earlier this can be confirmed by a test the better for everyone concerned, and if there is minimal risk of miscarriage even more so.
Although diagnostic invasive tests such as amniocentesis (where a sample of amniotic fluid is extracted from the amniotic sac surrounding your baby via a needle) can tell you whether your baby has certain chromosomal abnormalities, the test also carries a risk of miscarriage (around one in 150 women will miscarry after amniocentesis) and can only be performed when you have reached 16 weeks.
A Non Invasive Prenatal Test Scan (NIPT Scan)
The good news is that a new pregnancy blood test – not currently available on the NHS – is now available privately which is 98 per cent accurate in detecting Down’s Syndrome, a chromosomal abnormality which happens by chance at conception and causes learning difficulties and physical health problems.
The Harmony™ blood test can also detect other chromosomal abnormalities including Edwards’, Turners’ and Patay’s Syndromes. The Harmony™ blood test and NIPT scan can be performed from just 10 weeks after conception, and the results are available in two weeks. Furthermore, because it is a non-invasive prenatal test, there is no risk of miscarriage.
The test works by analysing fragments of your baby’s DNA (a complex chemical that carries genetic information) that circulate in your blood along with your own DNA. This material is called cell-free foetal DNA, is first detectable at around 4-5 weeks of pregnancy, and comes from your placenta. It doesn’t reach sufficient concentrations to be able to give you an accurate result until 10 weeks, though.
At Ultrasound Direct we offer the Harmony™ blood test in conjunction with a 30-minute diagnostic scan to check the viability of your pregnancy (your baby’s heartbeat) and foetal growth against dates. This package is called the Non Invasive Prenatal Test (NIPT) Scan and costs £499. We perform the NIPT scan before the blood test to check the pregnancy is viable as sometimes DNA fragments continue to circulate even if the foetus is no longer alive. It can be performed anytime between 10 and 22 weeks.
As part of the NIPT scan package we also offer a 4DFREEVIEW™ is a No Cost Option (available from 12 weeks) at no extra cost. We’ll show you your baby in live 4D from the Available Views* during your chosen scan with us and you’ll also receive thermal black and white 3D scan prints to take home.
What the Harmony™ blood test results can tell you
We take a blood sample, which is sent off for testing, and the results come back in two weeks. You will be told that the foetal DNA test result is either:
- Positive: This means there’s a high-predicted chance of your baby having Down’s Syndrome. You will need amniocentesis to confirm it.
- Negative: Highly unlikely that your baby will be affected by Down’s Syndrome or any of the other chromosomal abnormalities tested for and further tests are not usually needed or;
- Inconclusive: An insufficient sample of cell-free DNA was extracted in the blood sample (this happens in about 4-5 per cent of cases – the test can be redone at no additional charge).
Deciding if you want the Harmony™ test
Think carefully about whether you want to know if there is a problem with your baby’s health before you have the pregnancy blood test and about what you would do. To help you make up your mind, you can contact the charity Antenatal Results and Choices.
The main advantages of Harmony ™ can be summarised as:
- Performed from 10 weeks – six weeks earlier than amniocentesis.
- No risk of miscarriage associated with it.
- It’s not invasive and not an uncomfortable procedure such as amniocentesis.
- Tells you the sex of your baby if performed at 16 weeks.
The limitations of the blood test are:
- It’s not a diagnostic test, it can’t give you a definite yes or no answer about whether your baby has Down’s Syndrome, although studies have shown accuracy is around 98 per cent. If you get a result which finds you are at high risk of having a Down’s baby you will still need amniocentesis to confirm it.
- Sometimes not enough DNA is captured in the blood sample to get an accurate result and the test has to be repeated.
- Whilst Harmony ™can be used in twins, if the result is positive the test can’t tell you which twin is affected.
- Not as accurate in women who have a high Body Mass Index (BMI) because they have too much of their own DNA circulating in their bloodstream.