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Contents 6
Fetal DNA Test
A Reliable Method for Detecting Aneuploidy in Pregnancy
Pregnancy is a delicate period that requires careful monitoring to protect the health of both mother and baby. During this time, various screening and diagnostic tests are performed to follow the development of the fetus and detect possible chromosomal abnormalities. With the technological advances of recent years, the Fetal DNA test (Non-Invasive Prenatal Test – NIPT) has emerged as an important innovation in this field. The Fetal DNA test is a non-invasive screening test that offers high reliability in detecting conditions such as aneuploidy (an abnormal number of chromosomes) during pregnancy.
What Is the Fetal DNA Test?
The Fetal DNA test is a screening test performed by analyzing the fetal genetic material (fetal DNA) circulating in the expectant mother's blood. Throughout pregnancy, cells belonging to the fetus pass into the mother's bloodstream, and the fetal DNA contained within these cells is separated and analyzed using specialized laboratory techniques. This test is used particularly to screen for chromosomal abnormalities such as Down Syndrome (Trisomy 21), Trisomy 18, and Trisomy 13. Because it is a non-invasive method, the Fetal DNA test carries less risk than traditional methods such as amniocentesis and offers high accuracy rates.
How Is the Fetal DNA Test Performed?
The Fetal DNA test can be performed from the 10th week of pregnancy onward. The test is carried out on a blood sample taken from the expectant mother. The blood sample is sent to the laboratory, and the fetus's freely circulating DNA (cffDNA) is isolated. This isolated DNA is then used to examine the fetus's chromosomal structure. Results are usually available within 1-2 weeks, and the analyzed data show whether abnormalities are present in specific chromosomes.
In Which Situations Is the Fetal DNA Test Recommended?
The Fetal DNA test is a test recommended particularly for pregnancies in the high-risk group. It may be recommended in the following situations:
In pregnancies at age 35 and older, this test may be recommended because the risk of chromosomal abnormality increases.
Positive screening tests: The Fetal DNA test may be performed in pregnancies where the double, triple, or quadruple screening tests show a high risk of aneuploidy.
Family history of genetic anomaly: The Fetal DNA test may be recommended for expectant mothers who have a family history of a baby with trisomy.
Ultrasound findings: Certain anomalies detected on ultrasound in the fetus can be examined in more detail with the Fetal DNA test.
Blood incompatibility: If the mother's blood type is Rh negative and the father's is Rh positive, and there is a risk of blood incompatibility in the fetus, the Fetal DNA test may be performed.
What Are the Advantages of the Fetal DNA Test?
The Fetal DNA test offers many advantages compared to other screening and diagnostic methods:
Non-Invasive Method: Performed on the mother's blood, this test carries less risk than invasive methods such as amniocentesis or chorionic villus sampling (CVS).
High Reliability: The Fetal DNA test has an accuracy rate of over 99% in detecting chromosomal abnormalities such as Down Syndrome.
Early Application: This test, which can be performed from the 10th week of pregnancy onward, provides reliable information at an early stage.
Fast Results: Test results are usually available within 1-2 weeks.
What Are the Limitations of the Fetal DNA Test?
Although the Fetal DNA test is a highly reliable method, it also has certain limitations:
Does Not Provide 100% Certainty: The Fetal DNA test is a screening test and does not give a 100% definitive result. When results are positive, an invasive diagnostic test such as amniocentesis may be required for a definitive diagnosis.
Fetal DNA Fraction: The accuracy of the test depends on there being a sufficient amount of fetal DNA in the mother's blood. When this fraction falls below 4%, the test may not give an accurate result.
Limited to Specific Chromosomes: The test only screens for specific chromosomal anomalies. Different tests may be required for other genetic disorders.
The Fetal DNA test is becoming increasingly widespread as a reliable, non-invasive method for aneuploidy screening in pregnancy. Thanks to its high accuracy rates and the fact that it can be applied early in pregnancy, this test has become a recommended screening method particularly for pregnancies in the high-risk group. However, it is important to be aware of the test's limitations and to discuss the results with your doctor in detail. The Fetal DNA test does not provide a definitive diagnosis, but it can be used as an important screening tool with high accuracy rates. Based on the results of this test, further diagnostic methods may be pursued if necessary.