Non-invasive prenatal testing (NIPT)

If your first screen has shown that your baby has a higher chance of having either Down’s syndrome, Edwards’ syndrome, or Patau’s syndrome, this doesn't mean your baby definitely has one of these chromosomal conditions.

Your choices

Your choices are to have:

• no further tests
• a further screening test - non-invasive prenatal testing, known as NIPT
• a diagnostic test - chorionic villus sampling (CVS) or amniocentesis

Further testing can give you more accurate information about how likely it is your baby may have Down’s syndrome, Edwards’ syndrome or Patau’s syndrome.

People choose to have further tests or not for lots of different reasons. Your midwife will respect your choices and will keep your choices private.

Your midwife will tell you about support organisations that can help you and give you further information and support.

NIPT explained

NIPT is a blood test that is more accurate than the first pregnancy screening test. It's offered to women who are carrying a baby identified from previous screening tests as having a higher chance of having either Down’s syndrome, Edwards’ syndrome, or Patau’s syndrome.

Is NIPT safe?

NIPT is completely safe and will not harm you or your baby.

You’ll be offered the same screening choices if you’re pregnant with twins as you would be if you were pregnant with one baby. NIPT is not suitable if you're pregnant with 3 or more babies.

NIPT will give results about all 3 conditions. You cannot choose to be screened for Down’s syndrome only, or Edwards’ syndrome and Patau’s syndrome only, like in earlier screening.

During pregnancy the placenta releases some of its DNA into your bloodstream, so your blood has both your DNA and some from the placenta. This is what NIPT measures.

If NIPT finds more DNA than expected for chromosomes 21, 18 or 13 in your blood it could mean that your baby has Down’s syndrome, Edward’s syndrome or Patau’s syndrome.

Should I have NIPT?

If you don’t want to go straight to having a diagnostic test, your NIPT result may help you to decide whether to have one or not. It can also help you prepare for the arrival of a baby who may need additional care and support.

NIPT is not suitable for everyone

Your midwife will explain to you if there’s a reason you cannot have NIPT, for example, if you’ve had a recent blood transfusion, cancer or have a condition that involves chromosomes 21, 18, or 13.

What result could I get?

There are 3 possible outcomes from the test.

Low-chance result

Most women who have NIPT will receive a low-chance result. This means it’s unlikely your baby has Down’s syndrome, Edwards’ syndrome or Patau’s syndrome. If you get this result, you’ll not be offered any further tests for these conditions.

A low-chance NIPT result means there’s only a very small chance your baby will have one of the conditions:

• 1 in 1054 women with a low-chance NIPT result will have a baby with Down’s syndrome
• 1 in 930 women with a low-chance NIPT result will have a baby with Edwards’ syndrome
• 1 in 4265 women with a low-chance NIPT result will have a baby with Patau’s syndrome.

High-chance result

If you get a high-chance NIPT result, it doesn't mean your baby definitely has Down’s syndrome, Edwards’ syndrome or Patau’s syndrome, but it’s very likely.

You’ll be offered diagnostic testing which can tell you for definite. Whatever you choose, healthcare professionals will give you information and support.

No result

NIPT can sometimes give no result if there’s not enough DNA in the blood sample, or if there’s been a technical issue with the testing.

If you don’t get a result you can choose to either have a repeat NIPT, go straight to diagnostic testing, or have no further tests.

How accurate is NIPT?

If you get a high-chance result that your baby has one of the conditions, this will be confirmed in your baby:

• 91 times out of 100 for Down’s syndrome
• 84 times out of 100 for Edwards’ syndrome
• 87 times out of 100 for Patau’s syndrome

NIPT is better at identifying when babies have Down’s syndrome than when babies have Edwards’ syndrome or Patau’s syndrome.

This may be because babies with Edwards’ syndrome or Patau’s syndrome are likely to be smaller and have smaller placentas. This may mean less DNA from the placenta can be found in your bloodstream.

NIPT is more accurate for women who’ve already had a higher chance result from their first screening test.

No screening test is 100% accurate. If you have more questions about accuracy and the chances of your baby having a chromosomal condition, talk to your midwife.

Pregnancies with more than one baby

NIPT can be as accurate in identical twin pregnancies as if you were pregnant with 1 baby.

NIPT may be less accurate in non-identical twin pregnancies because there are 2 placentas releasing their own DNA. It may not be possible to know what type of twin pregnancy you’re having.

NIPT is not suitable for triplet pregnancies, or pregnancies with more than 3 babies.

You may have found out your baby has a high chance of having one of the conditions by having NIPT or during routine scans. Or, you may have chosen to have diagnostic tests and know for sure.

Your midwife will tell you which support organisations can give you more information about living with the condition your baby has, or is very likely to have.

Your midwife will also offer to refer you to a specialist team which includes specialist doctors, midwives, and other healthcare professionals. This team may be in another hospital. Your midwife will help you to understand who the specialists are and what they do.

If you need to choose what to do next, healthcare professionals and the organisations listed on this page can answer any questions you have and support you in reaching decisions.

Whether you choose to continue with your pregnancy or not, your choices will be respected and you’ll get the care and support you need.

Further information in other languages and formats

Public Health Scotland has produced a leaflet for expectant parents and their families who have been given a result that their baby has a higher chance of having either Down’s syndrome, Edwards’ syndrome, or Patau’s syndrome from their first-line screening tests.