Non-invasive prenatal testing (NIPT)

The non-invasive prenatal test, or NIPT, is a new, highly sensitive test that screens for Down syndrome and certain other abnormalities in a baby. In Australia, it’s available only in some specialist centres and is done in the first trimester of pregnancy.

The NIPT involves a simple blood test from 10 weeks’ pregnancy and won’t harm your baby.

What is the non-invasive prenatal test (NIPT)?

During pregnancy, some of the baby’s DNA passes into the mother’s bloodstream. The non-invasive prenatal test (NIPT) analyses the genetic information contained in this DNA to screen for a number of abnormalities. The test is particularly sensitive to Down syndrome.

NIPTs have been offered in private centres in Australia for about 5 years. They are sometimes referred to by different names, depending on the company that makes them and including Harmony, Generation and Percept. The NIPT involves a simple blood test and can be done from 10 weeks into the pregnancy.

What does it test for?

The NIPT is a safe and highly effective way of screening for conditions that include:

• Down syndrome (also called trisomy 21)
• Edwards syndrome (trisomy 18)
• Patau syndrome (trisomy 13)
• Turner syndrome

Some laboratories also test the gender of the baby and look for problems with the sex chromosomes.

The test detects many chromosomal abnormalities, but not as many as a diagnostic test such as amniocentesis. It cannot screen for genetic disorders such as cystic fibrosis, thalassaemia or sickle cell anaemia.

Why have an NIPT?

The NIPT is highly sensitive and picks up more than 99% of cases of Down syndrome. But it is still a screening test rather than a diagnostic test. This means it can only tell you whether there is an increased risk of having a baby with an abnormality, rather than give you a definitive answer.

The only way of knowing for sure whether your baby has Down syndrome is to have a diagnostic test such as chorionic villus sampling (CVS) or amniocentesis.

Most women in Australia are offered the combined first trimester screening to screen for Down syndrome. This combines results from a blood test, the mother’s age and an ultrasound scan (which measures the thickness of fluid behind the baby’s neck, called the nuchal translucency) to show whether the baby is at increased risk of Down syndrome. The advantage of this type of screening is that the ultrasound can pick up other problems with the pregnancy and estimate the age of the fetus.

You might choose to have an NIPT test if:

• your combined first trimester screening test shows you are at increased risk of having a baby with Down syndrome
• you did not have the combined first trimester screening test because it was too late or the test wasn’t available in your area
• you want to be sure you are at increased risk before you opt for diagnostic tests such as amniocentesis or CVS, which carry a small risk of miscarriage
• you are at increased risk (for example, if you are older or you have had a baby previously with Down syndrome or another chromosomal condition)

NIPT is a good option if you are willing to pay for it — the test is expensive and not covered by Medicare (see ‘How much does the NIPT cost’ below). You should also consider genetic counselling before you have an NIPT.

What to expect from your NIPT results

It can take up to 2 weeks to get the result of your NIPT. If the result is ‘negative’, ‘normal’ or ‘low risk’, your baby is unlikely to have any of the chromosomal disorders tested. If the result is ‘positive’, ‘abnormal’ or ‘high risk’, this means your baby is likely to be affected.

If you have an abnormal NIPT result, a diagnostic test such as CVS or amniocentesis can confirm the result. You should discuss your options with your doctor, midwife or genetic counsellor.

How much does the NIPT cost?

The NIPT is not currently available for rebate under Medicare or private health insurance in Australia. The costs depend on the type of test and where it is analysed. If the test is sent overseas, it can cost more. You may also need to pay for an appointment with your doctor to get a referral, as well as an ultrasound.

Although costs have come down in Australia, since some companies are now able to analyse the results locally, you can still expect to pay between $400 and $1,000 for an NIPT.

Where to get more information

You should speak with a genetic counsellor before getting an NIPT. You can find genetic counselling services near you using the healthdirect Service Finder here. You can read more about genetic counselling here.

If you have any questions about the NIPT or what to do with your results, you can call the Pregnancy Birth and Baby helpline on 1800 882 436 to speak with a maternal child health nurse, 24 hours a day 7 days a week. 

Sources: Babycenter (What is a non-invasive prenatal test?) , Mayo Clinic (Prenatal cell-free DNA screening) , NPS Medicinewise (Non-invasive prenatal testing for Down syndrome) , , NSW Health, Centre for Genetics Education (Prenatal testing: Special tests for your baby during pregnancy) The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (DNA-based non-invasive prenatal testing for fetal aneuploidy)