What is nipt testing in pregnancy

What is noninvasive prenatal testing (NIPT) and what disorders can it screen for?: MedlinePlus Genetics

Noninvasive prenatal testing (NIPT), sometimes called noninvasive prenatal screening (NIPS), is a method of determining the risk that the fetus will be born with certain genetic abnormalities. This testing analyzes small fragments of DNA that are circulating in a pregnant woman’s blood. Unlike most DNA, which is found inside a cell’s nucleus, these fragments are free-floating and not within cells, and so are called cell-free DNA (cfDNA). These small fragments usually contain fewer than 200 DNA building blocks (base pairs) and arise when cells die off and get broken down and their contents, including DNA, are released into the bloodstream.

During pregnancy, the mother’s bloodstream contains a mix of cfDNA that comes from her cells and cells from the placenta. The placenta is tissue in the uterus that links the fetus and the mother’s blood supply. These cells are shed into the mother’s bloodstream throughout pregnancy. The DNA in placental cells is usually identical to the DNA of the fetus. Analyzing cfDNA from the placenta provides an opportunity for early detection of certain genetic abnormalities without harming the fetus.

NIPT is most often used to look for chromosomal disorders that are caused by the presence of an extra or missing copy (aneuploidy) of a chromosome. NIPT primarily looks for Down syndrome (trisomy 21, caused by an extra chromosome 21), trisomy 18 (caused by an extra chromosome 18), trisomy 13 (caused by an extra chromosome 13), and extra or missing copies of the X chromosome and Y chromosome (the sex chromosomes). The accuracy of the test varies by disorder.

NIPT may include screening for additional chromosomal disorders that are caused by missing (deleted) or copied (duplicated) sections of a chromosome. NIPT is beginning to be used to test for genetic disorders that are caused by changes (variants) in single genes. As technology improves and the cost of genetic testing decreases, researchers expect that NIPT will become available for many more genetic conditions.

NIPT is considered noninvasive because it requires drawing blood only from the pregnant woman and does not pose any risk to the fetus. NIPT is a screening test, which means that it will not give a definitive answer about whether or not a fetus has a genetic condition. The test can only estimate whether the risk of having certain conditions is increased or decreased. In some cases, NIPT results indicate an increased risk for a genetic abnormality when the fetus is actually unaffected (false positive), or the results indicate a decreased risk for a genetic abnormality when the fetus is actually affected (false negative). Because NIPT analyzes both fetal and maternal cfDNA, the test may detect a genetic condition in the mother.

There must be enough fetal cfDNA in the mother’s bloodstream to be able to identify fetal chromosome abnormalities. The proportion of cfDNA in maternal blood that comes from the placenta is known as the fetal fraction. Generally, the fetal fraction must be above 4 percent, which typically occurs around the tenth week of pregnancy. Low fetal fractions can lead to an inability to perform the test or a false negative result. Reasons for low fetal fractions include testing too early in the pregnancy, sampling errors, maternal obesity, and fetal abnormality.

There are multiple NIPT methods to analyze fetal cfDNA. To determine chromosomal aneuploidy, the most common method is to count all cfDNA fragments (both fetal and maternal). If the percentage of cfDNA fragments from each chromosome is as expected, then the fetus has a decreased risk of having a chromosomal condition (negative test result). If the percentage of cfDNA fragments from a particular chromosome is more than expected, then the fetus has an increased likelihood of having a trisomy condition (positive test result). A positive screening result indicates that further testing (called diagnostic testing, because it is used to diagnose a disease) should be performed to confirm the result.

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NIPT Test (Noninvasive Prenatal Testing): What To Expect

Overview

What is the NIPT test?

NIPT stands for noninvasive prenatal testing. It’s a screening test offered during pregnancy to see if the fetus is at risk for having a chromosomal disorder like Down syndrome (trisomy 21), trisomy 18 (Edwards syndrome) and trisomy 13 (Patau syndrome). The test can also determine the sex of the fetus. It’s done by taking a sample of your blood, which also contains fragments of DNA from the fetus. DNA makes up a person’s genes and chromosomes, and gives healthcare providers a glimpse into the fetus’s genetic makeup. The blood sample is sent to a lab and analyzed for specific congenital disorders. NIPT can’t screen for all chromosomal or genetic conditions.

The NIPT test is also called cell-free DNA (cfDNA) screening or noninvasive prenatal screening (NIPS). It’s important to remember that a screening test estimates the likelihood of the fetus having a particular condition. It doesn’t diagnose a condition. NIPT testing is optional. Your healthcare provider will provide information about prenatal genetic testing and help you make an informed choice about your options.

What does the NIPT test screen for?

NIPT doesn’t test for all chromosomal conditions or birth disorders. Most NIPT tests screen for:

• Down syndrome (trisomy 21).
• Trisomy 18.
• Trisomy 13.
• Disorders affecting sex chromosomes (X and Y).

An extra chromosome causes Down syndrome, trisomy 18 and trisomy 13. Screening for sex chromosomes can help predict the sex of the fetus and can also screen for differences in the usual number of sex chromosomes. The most common sex chromosome conditions are Turner syndrome, Klinefelter syndrome, Triple X syndrome and XYY syndrome. Not all NIPT panels evaluate for the same conditions. It’s important to talk to your healthcare provider about what your NIPT is screening for.

Why is noninvasive prenatal testing done?

Noninvasive prenatal testing helps determine the fetus’s chances of being born with certain chromosomal disorders. Healthcare providers may recommend it if you:

• Have a child with a chromosomal abnormality.
• Have had an ultrasound that shows that the fetus may have an abnormality.
• Have had an earlier screening test that suggests a potential problem.

The American College of Obstetricians and Gynecologists (ACOG) used only to recommend NIPT for pregnant people considered high risk. However, it’s now recommended that providers offer NIPT to all pregnant people, regardless of risk.

Based on the results of the NIPT test, your obstetrician may recommend diagnostic tests. Diagnostic tests give a definitive answer about whether the fetus has a specific condition.

When should the NIPT test be done in pregnancy?

NIPT testing can be done as early as 10 weeks of pregnancy through delivery. There’s typically not enough fetal DNA in a pregnant person’s blood before 10 weeks of pregnancy.

How accurate are NIPT tests?

The accuracy of the test varies by the condition that it’s checking for. Other factors — like being pregnant with multiples, being a surrogate or having obesity — can affect NIPT results.

NIPT is about 99% accurate in detecting Down syndrome. The test is slightly less accurate for detecting trisomy 18 and 13. Overall, NIPT tests produce fewer false positives than other prenatal screenings like the quad screen.

Does the NIPT test show the sex of the fetus?

Yes, NIPT can predict the sex of the fetus.

Test Details

Is it necessary to get the NIPT test during pregnancy?

No, it’s not necessary. It’s a personal choice, and it’s normal to have questions. Your healthcare provider will discuss all your prenatal screening options, including NIPT. Many factors may go into your decision to have NIPT and prenatal genetic testing in general. If you’re having a difficult time or wish to discuss the screenings in more detail, a genetic counselor can help you understand the prenatal testing options and what may be a good fit for you.

How do doctors perform a NIPT test?

During this test, your provider takes a sample of your blood to look for abnormalities in the fetus’s DNA. Your DNA is inside all of your cells. Your cells are constantly dividing and creating new cells. When cells break down, tiny DNA fragments are released into your bloodstream. You have a small amount of the fetus’s DNA circulating in your bloodstream during pregnancy. The NIPT looks at these fragments of fetal DNA in your blood — known as cell-free DNA or cfDNA.

Your provider obtains a blood sample through a vein in your arm. They send this sample to a lab to analyze it for specific conditions.

It’s important to note that it takes about 10 weeks for enough fetal DNA to circulate in your blood. That’s why the screening isn’t performed until 10 weeks into the pregnancy.

Are there any risks to the NIPT test?

NIPT tests are safe, and there’s no risk to the fetus. It requires drawing blood from the pregnant person only.

Results and Follow-Up

When should I get my test results?

Results from NIPT tests can sometimes take up to two weeks, although results are often available sooner. Your healthcare provider will receive your test results first, then share the results with you.

What do the results of the NIPT test mean?

NIPT is a screening test, which means that it won’t give a yes or no answer about whether or not a fetus has a condition. The result will show if there’s an increased or decreased risk for a fetus to have the condition being screened. Your test results may sometimes be hard to interpret, so ask your healthcare provider for help if you’re unsure.

Most labs give separate results for each condition they’re screening for. For example, you may get a positive or high-risk result for trisomy 13 but a negative or low-risk result for Down syndrome.

There’s also the possibility that no test results are given due to insufficient fetal DNA in your blood or difficulty identifying fetal DNA. In this case, you can repeat the NIPT test and hope for a result the second time. Your healthcare provider can best guide you in these situations.

If noninvasive prenatal testing indicates that the fetus is at risk for a chromosomal disorder, your provider may recommend diagnostic testing. These tests diagnose conditions and give a yes or no answer:

• Amniocentesis: Amniocentesis is a procedure in which a small amount of amniotic fluid is taken from your uterus. This test can be performed after 15 weeks of pregnancy.
• Chorionic villus sampling (CVS): During chorionic villus sampling test, cells are taken from the placenta. The cell sample is sent to a lab. This test can be performed between 10 and 13 weeks of pregnancy.

It’s important to discuss the results of your NIPT with your provider so you have all the information you need to determine the next steps.

Can NIPT testing be wrong for Down syndrome?

NIPT is a screening test and, therefore, isn’t perfect. It’s important that you talk to your healthcare provider about your results and options to get more information.

Additional Details

Is the NIPT test worth it?

Getting a noninvasive pregnancy screening or other prenatal genetic test is up to you. Your healthcare provider can answer any questions you have, but ultimately you have to decide how a genetic or chromosomal disorder affects you and your family based on your situation.

The following questions might be helpful to you as you make your decision:

• How will I feel about a positive screening result?
• Would I consider diagnostic tests like amniocentesis or CVS?
• Would I do something different knowing the fetus has a genetic condition or an increased risk for a genetic condition?
• Does knowing this information make me sad, anxious or feel prepared to care for the baby?
• Would knowing this information help my provider(s) take better care of the baby?

How much does the NIPT test cost?

NIPT testing costs vary. Most health insurances cover most (if not all) of the cost. Many cover at least a portion. Check with your insurance provider before testing to be sure. If you don’t have insurance or your insurance doesn’t cover NIPT tests, you can pay for the test.

Can NIPT be done at 14 weeks?

Yes, NIPT can be done anytime after 10 weeks of pregnancy.

What questions should I ask my doctor about the NIPT test?

Noninvasive pregnancy screening tests are a personal choice. You may have questions about what your results mean or if you should even have the NIPT test. Don’t be afraid to ask questions. Remember, only you and your family can decide what’s best for you.

Some common questions to ask your healthcare provider are:

• Would you get the NIPT test if you were me?
• If my screening test is positive, what are the next steps?
• Is a genetic counselor available to talk to me about my options?
• What are the chances of false positives?

A note from Cleveland Clinic

The NIPT test is a highly reliable prenatal screening tool that assesses the risk of chromosomal disorders in a fetus. This test can also provide information about the sex of the fetus. NIPT testing doesn’t diagnose conditions — it only suggests a fetus is more likely to have a particular condition. Diagnostic testing may be recommended after you get NIPT test results. Prenatal tests like NIPT are optional, and getting the test is entirely up to you. Talk to your healthcare provider or a genetic counselor about your concerns. Be sure to understand what the test screens for and what the results mean so you make an informed decision.

Non-Invasive Prenatal Test (NIPT)

The generally accepted methods of prenatal diagnosis of fetal pathology are "double" and "triple" tests - screening of the 1st and llth trimesters of pregnancy in combination with ultrasound. However, for all their merits, the accuracy of these studies in relation to frequent chromosomal abnormalities is ~80%. The accuracy of a non-invasive test is much higher than that of biochemical screening, since its results are not affected by the characteristics of the course of pregnancy, the drugs taken, and the woman's somatic diseases. For example, the most common symptoms can be recognized with maximum certainty:

Down syndrome >99%

Edwards syndrome >98%

Patau syndrome ~98%

Advanced NIPT recognizes all the pathology that is included in the standard plus five microdeletion syndromes: crying cat, 1p36, Prader-Willi, Angelman, DiGeorge.

An important advantage is that non-invasive diagnostics is also the safest way to diagnose fetal chromosomal disorders. Unlike various invasive methods such as cordocentesis, amniocentesis and chorionic villus aspiration, this test is done on the mother's blood and is absolutely safe for both her health and the health of the unborn child.

For the test, venous blood is taken from the mother and the DNA of the fetus is analyzed, which enters the bloodstream of the pregnant woman from the placenta. The test detects the presence of a violation of the number of chromosomes (aneuploidy) of the fetus. Aneuploidies are the causes of congenital genetic diseases of the child, which can have a significant impact on his physical health and mental abilities. nine0007

• 10 days will be required for the study.
• The test was put into practice in 2012 and has since been successfully used worldwide. Since 2013, more than 6,000 non-invasive genetic tests have already been performed at Mother and Child clinics.

Since the non-invasive genetic test is an absolutely safe diagnostic method, any pregnant woman who wants to get the most complete information about the health of her unborn child and dispel unnecessary doubts and fears can do it. nine0007

1. The age of the pregnant woman is over 35 years.

2. High risk on biochemical screening.

The test can be taken from 10 weeks of pregnancy, but leading geneticists recommend that you first undergo an ultrasound screening of the first trimester at 11 weeks and, if the result is good, do not go for blood biochemistry, but do NIPT instead.

Blood for testing is not taken on an empty stomach. It is advisable to eat something sweet before donating blood for the study. The analysis is not affected by drugs, medicines or vitamins taken during pregnancy.

When donating blood for a test, the fetal DNA fraction (the amount of fetal DNA circulating in maternal blood) must be at least 4%. In the case of a reduced amount (less than 4%), a blood sample may be required. Also, the second attempt is likely with increased body weight of the pregnant woman. nine0007

1. The presence of ultrasound markers of chromosomal pathology (such as the expansion of the thickness of the collar space, non-immune dropsy, hypoplasia of the nasal bone, shortening of the length of tubular bones) or malformations.

2. Carrying a balanced chromosomal rearrangement by one of the parents.

3. The presence in the family of a child with a genetic pathology. In all these cases, consultation with a geneticist and karyotyping of the fetus is necessary. nine0007

Previously, NIPT was not allowed for twins, surrogacy, donor programs, or after stem cell treatment or bone marrow transplantation. But science has stepped forward, and all this is no longer a contraindication.

The most important test for an expectant mother

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NIPT - The most important test for expectant mothers

Pregnancy and children are wonderful! But what is even more wonderful is to be sure that your child is healthy and developing correctly.

NIPT (Non-Invasive Prenatal Test ) is a study of the genetic material of a baby, originating predominantly from the placenta, which appears in a woman's blood from the 4-5th week of pregnancy.

NIPT is absolutely safe for the baby: for this test, blood is taken from a pregnant woman from a vein, extracted from this sample of fetal DNA and examined. nine0007

By the 9-10th week of pregnancy, there is enough baby DNA in the mother's blood to determine if the unborn baby has chromosomal abnormalities that occur by chance.

Why can't this important study be done before 9-10 weeks? In order to correctly perform NIPT, we need more than 4% extracellular DNA of the fetus in the blood of the expectant mother. Typically, this level of concentration is achieved precisely for a period of 9-10 weeks or more, up to childbirth.

Indications for the study:

• parents' wish;
• intermediate risk (1:101 – 1:1000) based on first trimester combined screening;
• refusal of invasive prenatal diagnostics (puncture) or the presence of current contraindications to it;
• missed/incomplete first trimester combined screening.

There are 2 main types of NIPT:

1.t Arget test in anomalies 5 chromosomes: 13, 18, 21, X, Y (cost 20 900 in St. Petersburg) and

2. Full-begenomic test on anomalies of all chromosomes (cost 23,000 in St. Petersburg).