Prenatal tests and the 20 week scan
Many expectant parents wonder whether everything is alright with their child. Fortunately, that’s almost always the case. The combined test can investigate how likely it is that your child has Downs syndrome. As of April 1, 2017 NIPT is first choice. NIPT finds more children with Down- Edwards and Patausyndrome and the result is true more often then the result of the combined test.
Testing or not?
Testing can provide reassurance about the health of your child, but may also make you worried because of an unfavorable outcome and ask you to make difficult choices. You decide whether you want to do the test and whether you want to do further testing in an unfavorable outcome. You can always stop. Click here for the KNOV leaflet about NIPT.
When you’re considering to test, we talk to you about it usually during your first check at our practice. On the RIVM website you can prepare for this conversation. A decision aid also has recently become available on the website onderzoekvanmijnongeborenkind.nl.
The test is not covered by insurance. NIPT costs kost € 175. After we gave you a testing form you can pay through Niptbetalen.nl via IDEAL. You get a receipt in your mailbox. You have to print this out and take it to the blood collection point, together with your testing form. Amniocentesis and chorionic villus sampling are covered by insurance for women over 36 or women with an increased risk after the combined test. If in doubt, contact your health insurer. Click here for an overview of the costs.
Down syndrome is an inherited disorder that is caused by an extra chromosome 21. All children with Down syndrome are mentally handicapped. The severity varies from one child. Children with Down syndrome have specific physical characteristics. Almost half of children with Down syndrome are born with a heart defect. Also gastrointestinal disorders are common.
Patausyndroom is caused by an extra chromosome 13. Most children with patausyndroom die during pregnancy or shortly after birth. They always have severe intellectual and physical disabilities.
Edward’s syndrome is caused by an extra chromosome 18. Most children with Edward syndrome die during pregnancy or shortly after birth. They always have severe intellectual and physical disabilities.
The older the mother, the greater the chance of having a child with a chromosomal abnormality. The chance for a pregnant woman of 35 years for example, is 1 to 350 for a child with Down syndrome. This means that from 350 pregnant women aged 35, 349 children won’t be having Downs syndrome and 1 will.
Age of the pregnant woman Chance for Down syndroom
25 jaar ——————————————- 1 op 1400 (0,07 procent)
30 jaar ——————————————- 1 op 900 (0,11 procent)
35 jaar ——————————————- 1 op 350 (0,3 procent)
40 jaar ——————————————- 1 op 100 (1 procent)
45 jaar ——————————————- 1 op 20 (5 procent)
If you have a favorable outcome in the combined test the age risk is gone. However, women aged 36 and older still have the right to have an amniocentesis or chorionic villus sampling, even if there is no increased risk to the combination test.
NIPT means Non Invasive Prenatal Test. In the mother’s blood it can be tested if the unborn child has trisomy 21, 18 or 13. The mothers blood always contains a few pieces of genetic material(DNA) from the placenta. This DNA almost always matches the DNA from the baby. This is how the laboratory can check if the baby has Down-, Edwards of Patau syndrome. Click here for more information about NIPT. NIPT is the first choice above the combined test. It doesn’t offer a 100% guarantee , but if NIPT doesn’t show any abnormalities, further research doesn’t need to be done. When it does show abnormalities, there will always be an amniocentesis or chorionic villus sampling. You can only do NIPT when you participate in a scientific study (TRIDENT-2).
The laboratory can also find other chromosome abnormalities in the child, the placenta and in very rare cases even in the pregnant woman herself. This is called additional findings.There are various types of additional findings from very serious to less serious conditions. in 1,000 pregnant women who opt for NIPT, about 4 women are told that there is an additional finding. To be sure what kind of additional finding has been found, it is needed to do further research, usually amniocentesis or chorionic villus sampling.
Chorion Villus Biobsy
In CVB they take away a small piece of the placenta.This can be done in two ways.Through the vagina, through the cervix up to about 11 weeks, or through a small hole through the abdominal wall from 11 weeks of gestation. After CVS there is a small risk of miscarriage. Your risk is about one-half percent (1 in 200). You will get the result is after about 7 to 10 days. When it shows an abnormal result, there will always be an amniocentesis to rule out that the abnormality only occurs in the placenta.
In amniocentesis they take a bit of amniotic fluid through the maternal abdominal wall out of the uterus with a thin needle. An amniocentesis can be performed from the 15th week of pregnancy. The risk of miscarriage is approximately similar to that of CVS. The result of the amniocentesis is after about 3 weeks. This result is 100% sure. If it appears that there is a chromosomal abnormality parents can choose if they want to continue the pregnancy or abort.
Important to realize
If the result of NIPT doesn’t show any abnormalities, it’s 99.9% sure your baby does not have Down’s or Edwards or Patausyndrome. No further research has to bedone.
If the result does show abnormalities, this does not mean that your baby has a chromosomal abnormality. In the case of Down’s syndrome this is true in 75% of cases, in the case of Edward’s Syndrome this is true in 24% of cases, and in case of Patausyndroom this is true in 23% of cases. So there is a chance that your child does not have the chromosomal abnormality. If you want to be sure, you can take a chorionic villus sampling or amniocentesis. Are you thinking about ending the pregnancy? Then you first need to do further research to be sure.
20 week ultrasound scan or anomaly scan (SEO)
The 20 weeks echo can be made between the 19 and 22 weeks of pregnancy. In this echo, it is possible to assess the baby’s organs. We look at the brains, skull, face, spine, heart, stomach, intestines, kidneys, bladder and extremities. We also look at the amount of amniotic fluid, the position of the placenta and the growth of the child. Usually it is possible to look at the gender, but this is not the purpose of the echo. In a 20 week ultrasound large abnormalities of the organs of the baby usually are traced. Smaller abnormalities can be missed, and there are also diseases that can not be seen on an ultrasound. A good result of an ultrasound is no guarantee of a healthy child. The 20 week ultrasound is not intended to detect Down syndrome.
Read the brochure of the KNOV about the 20 week ultrasound.
Whether or not a 20 week ultrasound
A 20 week ultrasound, just like the NIPT or combined test, is not a compulsory examination, it is an examination which you choose for yourself. You should think about what you would do in case of abnormal findings.
Benefit of the 20 week ultrasound
Usually we see a normally developing child on the ultrasound, this is reassuring for expectant parents.
When abnormalities are found you can be prepared, and you can take into account what is the best place where the baby should be born. The disadvantage of the 20 week ultrasound
It is good to realize that not all abnormalities could be seen on an ultrasound and it can also make you worried. Occasionally there will be doubts about little things that are seen and then we repeat the ultrasound. Sometimes these abnormalities are not seen again or turn out not to be serious. Very occasionally there is an abnormality that is so serious that you get the choice to terminate the pregnancy. This is obviously very stressful.
The 20 week ultrasound is covered by insurance. If a follow-up study in the hospital is necessary, these costs are also covered by your health insurance. It depends on your own risk how much you have to pay yourself. Check with your insurer.