Non-invasive prenatal test

What is non-invasive prenatal testing?

The non-invasive prenatal test or fetal DNA test allows revealing genetic abnormalities of a fetus by a non-invasive test in maternal blood from the tenth week of gestation. In recent years it has proved to be an important alternative to invasive procedures such as amniocentesis, which can put the fetus at risk.

The results position it as a revolutionary technique, since it offers a 99% detection rate for the analysis of trisomy 21 (Down syndrome) and 95% for trisomies 13 and 18; no malformations are detected. Non-invasive prenatal diagnosis is not recommended if a blood transfusion or bone marrow transplant has been received in less than six months. Although it has been used clinically in Spain for a couple of years, it has not yet become widespread due to its high cost.

Some of the tests offered on the market are: extended non-invasive test, Karyosafe advanced non-invasive test, Harmony Test non-invasive test, KaryoSafe plus non-invasive test, Tranquility non-invasive prenatal test.

The non-invasive prenatal test or fetal DNA test can reveal genetic abnormalities.

What does it consist of?

This test is performed by analyzing maternal blood, since part of the DNA of the fetus is circulating in the mother’s blood. In this way it is possible to isolate the circulating DNA and analyze part of the genome belonging to the fetus, which has opened up a promising future with respect to the diagnosis of many anomalies.

Between 5 and 6 chromosomopathies and also other diseases related to microdeletions are performed, but in the future it is hoped to be able to assess the entire human genome.

Why is it performed?

The test is indicated for pregnant women of at least 10 weeks gestation. And it is especially advised in the cases of:

  • Mothers of advanced age
  • When the risk index for Down syndrome is high.
  • When there are risk factors for fetal chromosomal abnormality.
  • Obtaining extra information about the baby
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The specialist in Gynecology will prescribe this test depending on the history and the particular case. It is also possible to detect fetal sex in maternal blood using this test.

Preparation for the non-invasive prenatal test

Before the test is performed, an ultrasound is necessary to confirm the exact date of the pregnancy and to rule out abnormalities that may affect the test results.

What does the test feel like?

Blood is drawn from the inside of the arm. A tourniquet is used on the upper arm to slow the blood flow and allow the vein to swell. Before injecting the needle, the skin is cleaned with alcohol and absorbent cotton, thus disinfecting the area.

A needle extracts the blood and once it is taken, pressure is applied to the area. Afterwards, a small piece of gauze can be used to cover the wound. The blood collection is not painful, but it can be a little uncomfortable.

The blood sample is used to analyze fetal DNA as it circulates in the mother’s bloodstream. In this way, the baby’s chromosomes are analyzed and any genetic abnormalities are detected.

Significance of abnormal results

The non-invasive prenatal test can detect various abnormalities, so if the results are abnormal we could find that the fetus has one of the following pathologies:

  • Fragile X syndrome.
  • Trisomy 21 or Down syndrome
  • Trisomy 18 or Edwards’ syndrome
  • Trisomy 13 or Patau’s syndrome

If the results are altered, the specialist may request other invasive diagnostic tests such as amniocentesis or chorionic villus sampling to confirm if the result is positive.

If you need to perform a non-invasive prenatal test, you can buy it online and choose the laboratory closest to you.