Non-Invasive Prenatal Test (NIPT)

All the information you need about the NIPT

When you're pregnant you want to know whether your baby will be healthy. The earlier this can be confirmed by a test the better for everyone concerned.

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.

The NIPT has no risk of miscarriage and can be performed from 10 weeks. This article will tell you all about the NIPT.

What does the NIPT do?

The NIPT is a blood test to detect Down's syndrome, Edwards' syndrome and Patau’s syndrome. These are all chromosomal abnormalities which happen by chance at conception and can have serious effects on your baby's development, health and lifespan.

The NIPT test will detect 99% of pregnancies where a high probability of Down's syndrome, Edward’s syndrome or Patau’s syndrome is present.

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 high concentrations to be able to give you an accurate test result until 10 weeks.

What happens at a NIPT appointment?

At the Ultrasound Direct NIPT appointment we provide a 30-minute appointment with a diagnostic ultrasound scan to check the wellbeing and growth of your baby and viability of your pregnancy. One of our highly qualified sonographers will perform the scan and talk you through everything they see.

During this scan we can offer you a look at baby in beautiful 4D with our free of charge 4DFreeview option from 12 weeks, and offer our professional opinion about the sex of your baby from 16 weeks (also free of charge). Both of these are optional, so it's up to you.

After the scan, one of our fully phlebotomy trained colleagues will draw two vials of blood from your arm.

What happens with my blood?

Ultrasound Direct sends your blood sample to our partner laboratory, where the foetal DNA is tested using the Harmony Test at TDL. You will get the results of the blood test up to 7 working days after they are sent to the lab.

What do my NIPT results mean?

If the results of your Ultrasound Direct NIPT show a low probability of the chromosomal conditions being tested, you’ll receive a report via email. If the results show a high probability, a specialist member of our team will call you to discuss your results and your possible next steps.

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 one of the chromosomal abnormalities. Further testing will be required to confirm this.

  • Negative
    It's highly unlikely that your baby will be affected by any of the chromosomal abnormalities tested for and further tests are not usually needed

  • Inconclusive
    An insufficient sample of cell-free DNA was extracted in the blood sample (this happens in about 1% of cases)

Should I have a NIPT?

You need to think carefully about whether you want to know if your baby has a chance of being born with one of these chromosomal abnormalities before you have the NIPT. It's also a good idea to think about what you would do if the test came back with a high probability. You can find resources and support to help with this at the charity Antenatal Results and Choices.

Advantages of the Harmony NIPT

  • Performed from 10 weeks - six weeks earlier than amniocentesis

  • No risk of miscarriage associated with it

  • It's not invasive or uncomfortable

  • The Ultrasound Direct NIPT also gives you a chance to view baby in 4D and find out the sex

Disadvantages of the Harmony NIPT

  • It's not a diagnostic test - it can't give you a definite yes or no answer about whether your baby has one of the chromosomal abnormalities and further testing will be required

  • 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

  • The test is 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

You can find out more information about the NIPT here, including answers to Frequently Asked Questions, here.