Non-invasive prenatal test, when to do and how to interpret?

The non-invasive prenatal test It is a test with which be able to detect chromosomal changes in fetal DNA by maternal blood. Provides 99% reliability and It poses no risk to the mother or fetusbe able to perform from the 10th week of pregnancy.

By simple extraction of maternal blood, free DNA circulating in maternal plasma can be detected. So, through sequencing technology and advanced bioinformatic analysis, allows to know the sex of the baby and detect possible chromosomal abnormalities such as trisomy 21 (Down syndrome), trisomy 13 (Patau syndrome), trisomy 18 (associated with Edwards syndrome), and aneuploidies associated with the sex chromosome pair.

When to do the non-invasive prenatal test?

One of the great advantages of the non-invasive prenatal test is that it can be performed between weeks 9 and 10 of pregnancy. At that point, it should be the gynecology specialist who recommends the conduct of the test and the optimal time for each patient, according to their history and circumstances of pregnancy.

In addition, because it is a test that affects neither the mother nor the fetus, it can be of great help to any woman expecting a baby, whether it is a single or multiple fetus. However, it is a test especially recommended for women whose mother age is 35 years or older, because the older the mother, the greater the risk that the baby will suffer from a genetic problem. It is also highly recommended if an ultrasound shows any suspicion of genetic problems in the fetus, if the mother has already had chromosomal changes in other pregnancies, or if the mother already has genetic changes that could affect the fetus.

How to interpret the results of a non-invasive prenatal test?

The non-invasive prenatal test allows screening and detection of possible fetal chromosomal abnormalities during pregnancy. It is a minimally invasive test to make sure there is no type of chromosomal abnormality, but how do you interpret the data from this prenatal test?

After the test is performed, results are usually in 7-10 days. Conclusions can then be drawn on the basis of the data obtained. Please note that the test results are numerical and the result will be based on a percentage:

• • Low risk or negative: when the test is negative or low risk, it means that there is hardly any chance of chromosomal changes.
  • High risk or positive: If the test is positive, other diagnostic tests should be performed to confirm the chromosomal change with certainty.
  • Inconclusive: in some cases, the non-invasive prenatal test is inconclusive. If this happens, it is recommended to repeat the test some time later.