Everything About your pregnancy

Prenatal testing

Prenatal screening includes examinations concerning the health of the baby. These examinations/tests are optional.

Prenatal screening includes testing for Down, Edwards, and Patau syndrome. The second examination is the 20-week ultrasound.

Testing for Down syndrome, Edwards syndrome and Patau syndrome:


Children with Down syndrome have an intellectual disability and more health problems. Their development capabilities may vary.

Children with Edwards or Patau syndrome often die before or around birth. They rarely make it to the age of one. These children often have serious physical abnormalities and severe intellectual disability.

Prenatal testing

What tests are there?

Two tests are available, the NIPT test and the combination test.


The NIPT (non-invasive prenatal test) is a blood test for the pregnant. The blood contains DNA from the baby’s placenta, which is what is tested.

The NIPT detects Down, Edwards and Patau syndrome in children, and the result of the NIPT is more accurate than the result of the combination test.

The NIPT does not pose any risk to the pregnancy.

If there is an indication, resulting from the NIPT, that the baby has one of the syndromes, you can opt for chorionic villus sampling or amniocentesis.

The costs of the NIPT are not covered by health insurance.

The combination test:

Until 2017, this was the only way to test for the syndromes.

The combination test provides a probability calculation for whether the baby has Down syndrome, Edwards syndrome, or Patau syndrome.

The combination test requires three results:

  • A blood test for two hormone values, between 9 and 14 weeks of pregnancy
  • An ultrasound to measure the baby’s neck fold between 11 and 13 weeks of pregnancy
  • The age of the mother

The result you receive is a probability calculation. The test does not provide any certainty as to whether your baby has any of the aforementioned syndromes. There are no risks associated with the combination test.

A low probability is 1 in 201 or lower. The test is final and you will not be able to conduct any further research.

A high probability is 1 in 200 or more. In this case, you can opt for further research.

Further research can be carried out by a NIPT or by amniocentesis or chorionic villus sampling.

This is at your own cost, you may be able to get this covered by your health insurer.


For the differences between NIPT and the combination test, to gain insight into whether a test fits your wishes, and further information, please visit the following website:

Continuation after a indication of deviation

Amnion punction


If there is an abnormality indication from the NIPT or the combination test, you will be given the option to have amniocentesis or chorionic villus sampling done. You will be referred to the Erasmus MC for this.


You can read more about the NIPT and the combination test in the brochure: ‘Information about prenatal screening’.

The 20-week ultrasound:

The 20-week ultrasound:

This ultrasound is called the structural ultrasound examination.

This ultrasound can be performed for the examination of certain physical abnormalities in the baby, done around 20 weeks of pregnancy. It also examines the development of the baby’s organs, whether the baby is growing well and that there is sufficient amniotic fluid.

Participation is voluntary, and costs are covered by health insurance.


Examples of abnormalities that can be seen with this ultrasound:

  • Spina bifida (gap in the spine)
  • Anencephaly (gap in skull)
  • Congenital hydrocephalus (too much fluid in the brain)
  • Heart defects
  • Defect in diaphragm
  • Defect in the abdominal wall
  • Abnormalities in the intestines
  • Missing or abnormal kidneys
  • Missing or abnormal bones
  • Abnormality of arms or legs


The 20-week ultrasound is a reasonably reliable method for detecting serious birth defects. However, this research does not guarantee a healthy baby. Not all conditions can be seen on the ultrasound!

If a physical abnormality is detected in your unborn child, the consequences are not always clear.


Read here the official folder about the 20-week ultrasound in English or other language. 

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