When you are a pregnant mother, it is normal to have many questions about the little one in your womb. To find answers to some of these questions, we do various tests (prenatal testing) during pregnancy. So one of these special tests is called NIPT. This can give us a clue as to whether your baby is at risk of developing certain genetic conditions, such as Down syndrome . However, this is not a 100% specific test. Therefore, some doctors prefer to call it NIPS (screening) rather than NIPT (testing). Because this only indicates the risk.
How to do the NIPT test? It's very simple!
We've all heard of DNA. It's like a book that's in every cell in our body, holding all of our genetic information. Did you know that tiny pieces of this DNA are also floating around in our blood. We call this cell-free DNA, or `cfDNA`?
So when you're pregnant, your blood contains your own `cfDNA`, along with fragments of your baby's DNA (cell-free fetal DNA - cffDNA) . Isn't that amazing? The NIPT test involves taking a simple blood sample from you and testing it for fragments of your baby's DNA, giving you clues about certain genetic conditions. Since it's a noninvasive test, there's no risk to you or your baby.
What can we learn from the NIPT test?
The NIPT test mainly looks for abnormalities in chromosomes. Simply put, chromosomes usually come in pairs in our cells. But sometimes, instead of two copies of a chromosome, there can be three. We call this trisomy .
Here are the main trisomy conditions that the NIPT test looks for and their accuracy:
| Genetic condition | Chromosome number (Trisomy) | NIPT Accuracy |
|---|---|---|
| Down syndrome | Trisomy 21 | ~99% |
| Edwards syndrome | Trisomy 18 | ~97% |
| Patau syndrome | Trisomy 13 | ~87% |
Please remember: NIPT is only a screening test that indicates whether there is a risk. It cannot be 100% certain that a disease is present.
If the NIPT result is positive, meaning it indicates a risk, we need to go for a diagnostic test to confirm it. There are two tests that are done for that:
1. Amniocentesis: A procedure that involves taking a sample of amniotic fluid from inside the uterus and testing it.
2. Chorionic Villus Sampling (CVS): A procedure that involves taking a few cells from the baby's placenta and testing them.
Because both of these tests are invasive ( invasive ), there is a small risk. Therefore, some mothers may be reluctant to have them done.
Additionally, NIPT can also determine the baby's gender . If you don't want to know, don't forget to tell your doctor before the test.
Who wants to do the NIPT test?
This test can be done by any mother who has completed 10 weeks of pregnancy. However, it is not a mandatory test. However, mothers who are at high risk for certain genetic conditions are more interested in this.
Who is at higher risk?
- Mothers over 35 years of age.
- Mothers who have previously given birth to a child with a trisomy condition.
- Mothers who have been shown to be at risk by another screening test (e.g. first trimester screening).
Situations where NIPT results may not be very reliable
The NIPT test relies on the amount of baby DNA in the mother's blood. This amount is usually a small percentage, around 10%-20%. Therefore, some conditions in the mother's body can affect these results.
- If your body mass index (BMI) is 30 or higher.
- If the child was conceived with a donor egg.
- If you are using certain blood thinners.
- If you are carrying twins or more children in the womb.
In this case, it's best to talk to your doctor and decide if the NIPT test is right for you.
What do you do after receiving the NIPT results?
It's normal to feel sad and shocked when you find out that you have a risk (positive result) from an NIPT test. But don't panic. First, remember that this is not a final decision. At this point, it's very important to talk to a genetic counselor or your doctor to understand the results.
NIPT is only a risk-indicating test. Do not make any important decisions about your child based solely on that result.
If you want, you can go for a diagnostic test like the previously mentioned `amniocentesis` or `CVS` to confirm the situation 100%. Or you have the right to not have those tests. Talk openly with your doctor about all of these things.
Take-Home Message
- NIPT is a test that is performed using a simple blood sample taken from the pregnant mother and poses no risk to you or your baby.
- This is not a 100% definitive diagnosis. It is only a screening test that indicates the risk for conditions such as Down syndrome.
- If the NIPT result is positive, another test, such as amniocentesis, should be performed to confirm it.
- Always discuss NIPT results and next steps with your doctor, rather than making decisions on your own.
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