What is Prenatal Sreening?
Prenatal screening can help set your mind at ease about your child’s health. Fortunately, the vast majority of children are born healthy. However, it can also be a source of uncertainty and force you to face some difficult decisions.
What is the NIPT?
The NIPT (Non Invasive Prenatal Test) is a test whereby your blood will be analysed in a laboratory to test if your unborn baby might have a chromosomal or genetic abnormality. The most common chromosomal abnormalities are Down- , Edwards- or Patausyndrome; also known as trisomy 21, trisomy 18 or trisomy 13.
The blood test analyses the DNA of your child's placenta. Normally the placenta and child have the same DNA. The DNA normally consists of 23 pairs of chromosomes, what makes a it a total of 46 chromosomes.
When, for example, 47 chromosomes are seen during the NIPT screening, there may be a chromosomal abnormality. If you desire, this can be a reason for further research with prenatal diagnostics.
Are there other tests to determine chromosomal syndromes?
Yes. In the past, the combination test was the first choice. This test consists a blood sample from the mothers hormones (hormone values are analysed) and a ultrasound where the nuchal fold in the neck of the baby is measured. As result you receive a calculations of the odds of having a child with trisomy 13,18 or 21. For 3 years now, women with an increased chance in the combination test are eligible for the NIPT, the TRIDENT-1 study. The NIPT has proved to be more reliable than the combination test. So since April 2017, the NIPT is also available for pregnant women without an increased risk of having a child with a chromosomal abnormality as being the TRIDENT-2 study.
However, you can still opt for the combination test.
It’s good to know that both; the NIPT and the combination test are non-invasive examinations and therefore does not pose any risks of miscarriage for your child.
Do you not have a BSN number (condition for participation in Trident 1 and 2 study) and you still want to do the NIPT? Or do you want to know as early as possible if there is a chromosomal disorder? Or do you want to do more extensive research into the DNA of your child than the Trident study is currently doing; You can also choose to have a blood draw for the Panorama NIPT at Femme-Amsterdam; an American NIPT conducted by the world market leader Natera.
If the NIPT gives an indication of a chromosomal abnormality in your child, you have the option to choose for prenatal diagnostic testeing. With this test you can generally say with 100% guarantee whether your child has the chromosomal abnormality or not. Prenatal diagnostic tests are invasive tests, so it means it comes with a little risk of miscarriage. This is a risk of 1: 500, 0,2%.
What is the difference between the tests?
We have made the following schedule for you to clarify the difference in the tests:
|FAQ||Dutch NIPT; Trident 2 study||American NIPT; Panorama NIPT||Combination test|
|How is the test performed?||Blood collection in mother||Blood collection in mother||Blood collection in mother|
|Is this test used as a study?||Yes, this test is only offered in research form. You must give permission to use your data for scientific research otherwise you can not participate.||No, however, there have been many peer review studies in previous years, including two validated studies with more than 50,000 patients. So far, more than 1 million tests have been carried out all over the world.||No, this test has been offered for years in the Netherlands, your data will not be used for research|
|Method of screening?||The method used for screening is the so-called counting method, which can not be used in vanishing twin and triploidy||This is the only test in the world that uses the SNP technology that can also differentiate between free cells placental DNA and maternal DNA. This test can also be used in vanishing twin and triploidy||The blood level of the hormones PAP-A and βHcG is determined by means of a blood test. These provide a predictive value for carrying a child with chromosome aberration. Also the thickness of the neck fold (measured with echo) is included in the computer calculation|
|When can I do the test?||From 11 weeks of pregnancy||From 9 weeks of pregnancy||
Blood between 9 and 14 weeks of pregnancy
Ultrasound between 11 + 3 and 13 + 4 weeks of pregnancy
|How long does it take before I receive the results from the NIPT?||Within 12 days||Within 10 days||
Two days after the ultrasound if the blood has been taken a week earlier.
Otherwise 1 week after the blood draw.
|Does the test detect all children with trisomy 13,18 and 21?||
No the test is discovered *:
* the Trident 2 is still a study case; these results are based on N = 72,340 cases
|No, the test discovered:
- 99 out of 100 children with trisomy 21
- 99 out of 100 children with trisomy 18
- 99.2 from 100 children with trisomy 13
|No, the test is discovered
- 85 out of 100 children with trisomy 21
- 77 out of 100 children with trisomy 18
-65 out of 100 children with trisomy 13
|What is the positive predictive value of the test?||
When you get an increased risk for:
When you get an increased risk for:
- trisomy 13 -> 38% chance that the baby actually has trisomy 21, 62% chance that the baby has no trisomy 13
|In the combination test you get a result of 1: .... chance of having a baby with trisomy 21, 18 and 13.
At a probability of 1: 5 - 1: 200 you are eligible for the Trident 1 study. If there is also an increased risk, you can opt for prenatal diagnostic testing.
|What is the negative predictive value of the test?||
When the results say that there is no increase risk for:
When the results say that there is no increase for:
|Can the test screen for more chromosomal abnormalities?||
Yes, if you want to see more deviations than trisomy 13,18 and 21, they can also screen for side-effects.
Further research is needed for all secondary finding!
Yes, if you want to see more deviations than trisomy 13,18 and 21 they can also screen for the following deviations mentioned by name:
Chromosome abnormalities in the child, other than trisomy 13,18 and 21
22q11.2 deletion syndrome
XXX, XXY, XYY
1p36 deletion syndrome
Triploïdy / vanishing Twin
During the non committed first introduction at Femme-Amsterdam you can receive more information about these syndromes if you desire.
|Can the test also screen for sex?||No||Yes, Sensitivity and Specificity is 99.9%||No|
|What are the costs?||
Extended Panel screening:
|Website||www.meerovernipt.nl (Dutch only)||www.natera.com/panorama-test||https://www.rivm.nl/documenten/folder-informatie-over-screening-op-down-edwards-en-patausyndroom-engels-english|
Is prenatal Screening mandatory?
No. You are free to choose whether or not you want to undergo testing and whether you want follow-up testing if the results are unfavourable. You can decide to break off testing at any time.