Combined screening test

Combined screening test

The combined tests consists of a combination of two tests:

  1. A blood test of the blood of the mother in the period between the 9th and 14th week of the pregnancy. The blood is tested in a laboratory.
  2. An ultrasound scan measuring the nuchal fold of the foetus in the period between the 11th and 14th week of the pregnancy. All children have a thin layer of fluid in the nuchal fold under the skin in their neck. The thicker the skin fold in the neck, the greater the likelihood that the child will have Down syndrome, Edwards’ syndrome or Patau’s syndrome.


The combined test calculates the risk of your child having Down syndrome, Edwards’ syndrome or Patau’s syndrome. The test will not provide any certainty. In case of an increased risk of a child with Down syndrome, Edwards’ syndrome or Patau’s syndrome, you can decide whether you want to have additional follow-up testing done. This follow-up test will clearly show whether your child has any of these syndromes or not.

If the skin fold is 3.5mm or more, you will always be offered additional ultrasound testing. A thickened skin fold is not only an indication of Down syndrome, Edwards’ syndrome and Patau’s syndrome, but may also indicate other chromosomal abnormalities and physical disorders in the child, such as heart defects. In some cases, there is no clear cause for the thickened skin fold, and the child is born without any disorders.

In some cases, the ultrasound technician will discover other disorders during the nuchal fold test (additional findings). These are serious abnormalities, such as missing limbs or brains.

If you are taking part in the combined test, you will always be informed of any additional findings found during the ultrasound.