Non-invasive prenatal test (NIPT), also called non-invasive prenatal screening, is a method of determining the risk of a fetus being born with certain genetic abnormalities. This test analyzes free fetal DNA fragments circulating in the blood of a pregnant woman. The mother's blood circulation during pregnancy involves the free DNA mixture from the mother's own cells and the placenta. The placenta is a tissue of the uterus that connects the fetus and the mother's blood flow. DNA in placental cells is generally the same as the DNA of the fetus. Analysis of placental DNA provides an opportunity for early detection of certain genetic anomalies without damaging the fetus.

NIPT is commonly used to detect the presence of common chromosomal number disorders (excess or lack of chromosomes). NIPT is primarily used to detect anomalies of sex chromosomes in Down syndrome (trisomy 21 caused by extra 21 chromosome, trisomy 18 (caused by extra 18 chromosomes), trisomy 13 (caused by extra 13 chromosome), X and Y sex anomalies ( or male, sex abnormalities are reported in predicted cases). There are also extended NIPT tests, including cystic fibrosis, hemophilia, DiGeorge, Angelman, Prader Willi's syndrome etc., in addition to the above-mentioned general abnormalities. it is possible to screen close to 70 diseases.

Until now, the only way to control your baby's DNA was to take a sample of amniotic fluid (Amniocentesis), Cord blood (CB) or placenta tissue (CVS). There is a risk that all three of them will have a low rate or cause complications. NIPT, on the other hand, requires noninvasively taking blood from the pregnant woman's arm and does not pose any risk for the fetus.

Because NIPT is more reliable than screening tests such as first trimester screening or quadruple testing (blood test, nuchal translucency, etc.), it can recover many women from invasive procedures such as unnecessary Amniocentesis or CVS.

If your test result is negative, the risk of anomaly in your baby is low, and if it is positive, your doctor may recommend further testing (CVS, Amniocentesis, CB).

NIPT is a screening test, ie it does not give a definite conclusion whether a fetus has a genetic disorder. The test can only predict whether the risk of having a certain anomaly increases or not. The sensitivity of the test depends on the anomaly. Sometimes placental DNA may be different from fetus DNA, so the results for decision-making should not be used alone, without clinical information

In some cases, false positives (showing the risk of genetic anomalies even if the fetus is not actually affected) may be false negative (in some cases the fetus shows that the risk of a genetic abnormality is not increased even though the fetus is indeed chromosomal anomaly). Because this method analyzes both the fetus and the mother's free DNA, sometimes the test can detect the genetic condition in the mother. In order to define fetal chromosomal abnormalities, the fetus should have sufficient free DNA (4% minimum) in the bloodstream of the mother and this ratio corresponds to the 10th week of pregnancy. The free DNA rate of the fetus may lead to inability to test or false negative results. Low rate causes include very early testing, sampling errors, maternal obesity and fetal abnormalities.

Currently, NIPT is only used for women with high risk pregnancies. Many experts think that this method will be a standard test instead of more risky screening tests a day. This test should be performed once, at any time between 10 and 22 weeks (sometimes 9 weeks). The test can be performed to all women, but it is recommended routinely to women over the age of 35 and at high risk for genetic abnormalities.