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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.
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 or other chromosomal abnormalities. However, it is also possible that an abnormal result is not an indication of a baby with trisomy 21, 18 or 13 or other chromosomal abnormalities. 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.| Age of the mother | Chance of a child with Down syndrome |
|---|---|
| 20-25 years | 1 in a 1000 |
| 26-30 years | 1 to 2 in a 1000 |
| 31-35 years | 2 to 5 in a 1000 |
| 36-40 years | 6 to 15 in a 1000 |
| 41-45 years | 20 to 61 in a 1000 |
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:
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.
From 1 September 2021, pregnant women can also participate in the 13-week ultrasound in addition to the 20-week ultrasound. This is done in the context of the national, scientific IMITAS study.
The 13-week ultrasound is a medical examination that you can have done if you are between 12 weeks and 3 days and 14 weeks and 3 days pregnant. The 13-week ultrasound is not mandatory. With the 13-week ultrasound, you can have your child examined early in the pregnancy to see whether your child has serious physical abnormalities. During a 13-week ultrasound, the sonographer looks at the skull, heart, abdomen, arms and legs, spine, nuchal fold and placenta, among other things. The sonographer also checks whether the amniotic fluid is normal. At the 13-week ultrasound, your baby is smaller and less developed than around 20 weeks of pregnancy. That is why there is less visible than with the 20-week ultrasound. But some often serious abnormalities can already be seen, for example an open skull. Some abnormalities are less visible, such as heart defects. Sometimes the sonographer thinks he sees an abnormality, but after additional examination it turns out that there is no abnormality. It can also sometimes take a long time before there is clarity. The 13-week ultrasound may therefore make you (unnecessarily) anxious or insecure.
NOTE: If the sonographer has not been able to assess everything properly, he/she will perform a vaginal ultrasound. to offer. You will receive it immediately. If you do not want a vaginal ultrasound, you can refuse this. If not everything can be visualized with the vaginal ultrasound and there are no indications of abnormalities, the sonographer will write down what was not (yet) clearly visible. You can then choose to look again at the 20-week ultrasound at 20 weeks. It will then be later in the pregnancy and more will be visible.
You pay nothing for the 13-week ultrasound.
If you opt for the 13-week ultrasound, you will participate in a scientific study of the 13-week ultrasound (IMITAS study). By signing the consent form, you consent to the use of your data for the scientific study of the 13-week ultrasound. The data is stored in your care file and in the national database (Peridos www.pns.nl).
Very important: at the 13-week ultrasound, the sonographer must assess physical structures in a baby about 66mm. What can help with this ultrasound examination is:Between 18 and 22 weeks of pregnancy, there is the possibility of a Structural Ultrasound Examination (SEO). This ultrasound reveals clearly visible physical abnormalities. If no abnormalities are seen on this ultrasound, a specially trained sonographer will carry out this examination with an advanced ultrasound machine.
These 20-week ultrasounds are made in our midwifery practice. Your health insurer will reimburse the 20-week ultrasound. The 20-week ultrasound is not specific for detecting chromosome abnormalities such as trisomies. However, physical abnormalities may match certain chromosome abnormalities or other hereditary syndromes, so that invasive diagnostics (for example amniocentesis) can still be offered.
Even if no abnormalities are seen during the ultrasound, we cannot guarantee a 'healthy baby'. '. A number of abnormalities arise later, the baby is developing. Sometimes abnormalities are not visible on the ultrasound or they are missed due to, for example, an unfavorable position of the baby or an unclear image. In case of doubt or if we see an abnormality, we will refer you to the LUMC (Leiden University Medical Center) for follow-up testing.Very important: at the 20-week ultrasound, the sonographer must assess structures in the baby. What can help with this ultrasound examination is: