Prenatal screening

Prenatal screening allows us to estimate the chance that your baby has certain defects. The higher the age of the mother, the higher the risk of these defects. During the first appointment, we will give you elaborate information, and we will answer your questions. It can be a difficult decision whether or not to do prenatal screening. That is why we recommend you to read some information about prenatal screening before your first appointment.

Professional ultrasound centre

At our practice on the Scheveningseweg, we offer ultrasound imaging. You can make an appointment for the vitality and the due date ultrasound, the ETSEO and the 20-week ultrasound as well as for the NIPT test. This appointment can be followed by a checkup with your midwife to discuss the preliminary results.

Non-invasive prenatal test (NIPT)

DNA of the unborn child is present in the blood of all pregnant women. This knowledge was the basis of a non-invasive prenatal test that tests the DNA in the blood of the mother for chromosomal abnormalities of the child. This test is very reliable and safe. The NIPT can be done at 10 weeks pregnant and onwards. All we need is two vials of blood of the mother-to-be. The result can be normal or abnormal. An abnormal result of the NIPT could indicate the presence of the trisomy 21, 18 or 13. However, it is also possible that an abnormal result is not an indication of a baby with trisomy 21, 18 or 13. Therefore, in case of an abnormal result, to be certain, we need to do follow-up invasive tests. These tests are called a chorionic villus sampling test and amniocentesis. One of these tests is necessary to confirm the NIPT result.

Most NIPT results are normal. In case of a normal result, the chance of a baby with a trisomy is so small (smaller than 1 in a 1000) that we do not recommend to do a follow-up test. If pregnant women with a higher chance of a trisomy do the NIPT test and the result is normal, a chorionic villus sampling test or an amniocentesis are also not necessary. In 2% of women who do a NIPT test, the test fails and needs to be repeated. If the test fails a second time, a combined test, chorionic villus sampling test, or an amniocentesis is necessary.

For more information, see the folder on prenatal screening on screening for down-, edwards- en patausyndrome.


Before doing the NIPT, we like to see you for an appointment for counseling. You will also be asked if you agree with keeping your blood sample for further research for the NIPT. This is not mandatory. The result of the NIPT will not show the gender of the baby.

Age of the mother Chance of a child with Down syndrome
20-25 years1 in a 1000
26-30 years1 to 2 in a 1000
31-35 years2 to 5 in a 1000
36-40 years6 to 15 in a 1000
41-45 years20 to 61 in a 1000

Additional findings of the NIPT

Please consider whether you want to be informed about any additional results. Beside the trisomies 13, 18 and 21, the NIPT can also detect other trisomies, deletions or duplications of the chromosomes. Such abnormalities could have serious consequences for the health of your child. Whether or not you want to be informed about any additional findings is up to you. If any of the additional results of the NIPT are abnormal, additional invasive diagnostic testing will be done to obtain certainty about the outcome. The result of the NIPT takes 10 workdays. You will get the results of the NIPT from the health practice that referred you. You cannot do both the combined test and the NIPT.

When can you participate?

There are special circumstances when its is not possible to use the NIPT as screening test. In these cases must be turned to alternative forms of prenatal screening/ diagnostic:

  • The ultrasound shows a fetal abnormality, e.g. an increased nuchal translucency (NT ≥ 3.5mm)
  • You or your partner have a chromosomal abnormality.
  • You have a malignant tumor at the time of your application.
  • You had a blood transfusion, stem cell or organ transplantation or immunotherapy less than 3 months ago.

More info?

Prenatal screening

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