What can you get tested?

If you are pregnant, you can have tests to see whether the baby you are carrying has certain medical conditions or physical abnormalities. This is called prenatal screening.

You decide whether or not to have these tests.  

 Which tests can you have and when? 

infographic over het NIPT en SEO onderzoek, toelichting in Uitgeschreven tekst onder afbeelding

 

  • As of Week 10, the NIPT: test for Down syndrome, Edwards’ syndrome and Patau’s syndrome and choose whether or not to screen for secondary findings as well
  • About week 13, the 13-week scan: test for physical abnormalities, early in the pregnancy
  • About Week 20, the 20-week scan: test for physical abnormalities in the baby, almost half way through pregnancy,

When you see your midwife for the first time, you will be asked if you would like to know more about the NIPT and the 13 and 20-week scans.

There are two options:

  • You would prefer not to know. You will not receive any information and you will not have the tests;
  • You would prefer to know. You will have an in-depth consultation (free of charge).

In this consultation, you will be given information about the tests and what they identify. After the consultation, you will decide whether or not you want to go ahead with the test(s). The questions below may help you make up your mind:

  • How much do you want to know about your unborn baby while you are pregnant?
  • What will you do if you are told that your unborn baby has Down syndrome, Edwards’ syndrome, Patau’s syndrome or a physical abnormality?

The NIPT

What is the NIPT?

You can choose to have the NIPT if you want to know whether your unborn baby has Down syndrome, Edwards’ syndrome or Patau’s syndrome. These are all chromosomal abnormalities.

Chromosomal abnormality
We have chromosomes in every cell in our body and they are made up of DNA. DNA determines what our bodies look like and how everything in them work. There may sometimes be a problem with one of the 23 pairs of chromosomes. This is called a chromosomal abnormality.


People with Down syndrome have an intellectual disability. They are born with this condition. It is more serious in some babies than it is in others. The level of severity cannot be assessed before the baby is born.

Edwards’ syndrome and Patau’s syndrome are far less common than Down syndrome. They are both very serious disorders. Most children with Edwards’ syndrome or Patau’s syndrome die before or shortly after birth.

The NIPT may identify other chromosomal abnormalities as well. These are called secondary findings. You decide whether or not you want to know about them.

The NIPT is a blood test for which blood will be taken from your arm. Your midwife or gynaecologist will tell you where you can go to have this done. The lab will test your blood to see if your unborn baby might have a chromosomal abnormality. You can have blood taken from the 10th week of your pregnancy onwards. The NIPT is free of charge.

You will receive your test results within 10 calendar days. Although not 100% accurate, they do usually put women’s minds at rest: if the results show no abnormalities, there will be just a very small chance of there being anything wrong with your unborn baby. If the results show evidence of an abnormality, you can choose to have follow-up diagnostic testing.

Which results are possible?

  • There is no evidence of Down syndrome, Edwards’ syndrome or Patau’s syndrome
    The results show no evidence of any abnormalities.
    About 995 in 1,000 women get this result. It is almost always accurate. Less than 1 in 1,000 women are actually found to be pregnant with a baby with one of these abnormalities. No follow-up diagnostic testing is necessary.
  • There is evidence of Down syndrome, Edwards’ syndrome or Patau’s syndrome
    The results show evidence of abnormalities.
    About 5 in 1,000 women get this result. Your unborn baby may have Down, Edwards’ or Patau’s syndrome. The results will also indicate which of the three abnormalities your unborn baby might have.
  • The test is inconclusive
    The NIPT fails for about 20 in 1,000 women and is inconclusive. There can be different reasons for this. If the NIPT fails, you can have the test done again, which will mean having more blood taken. Four in five pregnant women will then have a successful NIPT.

Have you chosen to be told about secondary findings too?

You will be given these results as well.

  • No secondary findings were found
    The results do not show evidence of any abnormalities.
    About 996 in 1,000 women get this result.
  • Evidence of secondary findings
    The results shows evidence of an abnormality.
    About 4 in 1,000 women get this result.

The 13-week scan

What is the 13-week scan?

You can be tested to see if your unborn baby has a physical abnormality. A physical abnormality means that part of your unborn baby’s body looks different to how we expect it to look.

The 13 and 20-week scans are very similar. In both scans, a sonographer will use an ultrasound machine to see if your unborn baby has any physical abnormalities.

The sonographer will make a scan of your unborn baby by moving a transducer over your abdomen. The scan does not hurt and is not dangerous. Your unborn baby will not feel anything. The scan will take about 30 minutes.

You can have the 13-week scan done from 12+3 up to 14+3 weeks of pregnancy. In other words: as of 12 weeks and 3 days up to and including 14 weeks and 3 days. There is no charge for the 13-week ultrasound scan.

The results of the 13-week scan are not 100% accurate. The sonographer will not be able to see all the physical abnormalities possible. So, your unborn baby could still have abnormalities, even if none are visible in the scan.

The sonographer will give you the results straight after the scan:

  • No visible evidence of a physical abnormality. About 95 in 100 women get this result;
  • The sonographer has checked the baby but could not see everything clearly;
  • There is evidence of an abnormality. About 5 in 100 women get this result. You will be asked if you would like to have follow-up diagnostic testing.

Scientific study

In the Netherlands, you will only be able to have the 13-week scan if you participate in the scientific IMITAS study. It is investigating the advantages and disadvantages of the 13-week scan.


The 20-week scan

What is the 20-week scan?

You can be tested to see if your unborn baby has a disorder or physical abnormality. A physical abnormality means that part of your unborn baby’s body looks different to how we expect it to look. Physical abnormalities include spina bifida (an open spine), an open skull, hydrocephalus, heart defects, a hole in the diaphragm, a hole in the abdomen, structural abnormalities of the kidneys and structural abnormalities of the bones.

The 13 and 20-week scans are very similar. In both scans, a sonographer will use an ultrasound machine to see if your unborn baby has any physical abnormalities. But there are differences too. Watch the video about the 13 and 20-week scans.

The sonographer will make a scan of your unborn baby by moving a transducer over your abdomen. The scan does not hurt and is not dangerous. Your unborn baby will not feel anything. The scan will take about 30 minutes. There is no charge for the 20-week scan.

The results of the 20-week scan are not 100% accurate. The sonographer will not be able to see all the physical abnormalities possible. So, your unborn baby could still have abnormalities, even if none are visible in the scan.

The sonographer will give you the results straight after the scan:

  • No visible evidence of abnormalities. About 95 in 100 women get this result;
  • The sonographer wants to repeat the scan;
  • The sonographer has seen something that might be an abnormality. About 5 in 100 women get this result. You will be asked if you would like to have follow-up diagnostic testing;
  • The sonographer has seen something that might be an abnormality. No follow-up diagnostic testing is necessary. You will have another scan later in your pregnancy. The sonographer will then check if the small abnormality has disappeared.

Difference between NIPT, 13-week scan and 20-week scan

The NIPT and ultrasound scans are different tests that target different disorders and abnormalities. Neither test replaces the other.

  • The NIPT screens for Down syndrome, Edwards’ syndrome and Patau’s syndrome. These are all chromosomal abnormalities.
  • The 13 and 20-week scans are ultrasound scans that are used to identify physical abnormalities. The 13 and 20-week scans are very similar. The 13-week scan is done early in pregnancy, when the baby is smaller and less developed. Some (severe) abnormalities will be possible to identify. There is more time to do any follow-up diagnostic testing necessary at this stage in your pregnancy. 

Follow-up diagnostic testing

You can choose to have follow-up diagnostic testing if the NIPT has identified potential abnormalities. Or if the sonographer has seen something that could be an abnormality in the 13 or 20-week scan. Or if there are medical reasons for follow-up diagnostic testing.

If you would like more information about follow-up diagnostic testing, you will be given an appointment at a prenatal diagnostic centre. You will only decide what you want to do after this appointment. You may decide not to have follow-up diagnostic testing.

Follow-up diagnostic testing will usually confirm whether or not your unborn baby has an abnormality. The follow-up diagnostic testing offered after an NIPT will consist of one of the following two tests: 

  • A chorionic villus sampling test;
  • An amniocentesis.

Follow-up diagnostic testing after the 13 and 20-week scans will consist of the following:

  • A morphology scan (usually);
  • A blood test (sometimes);
  • A chorionic villus sampling test (sometimes);
  • An amniocentesis (sometimes).

In a chorionic villus sampling test, the doctor will take a small piece of the placenta and examine it. This can be done after week 11 of the pregnancy.

In an amniocentesis, the doctor will remove a small amount of amniotic fluid and test it. This can be done after week 15 of the pregnancy.

The chorionic villus sampling test and amniocentesis both carry a small risk of miscarriage. Two in 1,000 women who have these follow-up diagnostic tests will have a miscarriage.

The cost of follow-up diagnostic testing will sometimes be deducted from your insurance excess.

What happens to your data?

If you have decided to have prenatal screening, your healthcare professionals will keep your data in your care record. This is required by law.

Your data and the results of the NIPT test and ultrasound scans are stored in a national information system (Peridos). This makes it possible to ensure that tests run smoothly. Data and results are used to verify that care providers and laboratories are doing their work correctly (quality assurance). Data like yours is also used to calculate how many pregnant women choose to have prenatal screening.

The national information system is very secure. However, please tell your midwife if you do not want us to store your data the national information system. They will make sure that only anonymous data are kept in Peridos after your expected delivery date. So, you will be included in statistics, but no-one will be able to see your personal data.

Blood may be left over after your blood has been analysed in the NIPT laboratory. The laboratory will store this blood and the corresponding data in a secure system. Blood is kept for eight years.

In this situation, you will participate in the scientific IMITAS study and allow researchers to use your data in the future (a maximum of 15 years). You will sign a consent form for this.