From the first moment that a couple find out that hey are expecting a baby, o even before knowing so, what most worries them is if everything will be ok, if the newborn will present any malformations or any other alteration in their chromosomes.

If a prenatal screening test, your age, your family or medical history indicates a possible problem you might consider a prenatal diagnostic testing in order to provide valuable information about your baby’s health.

To be able to diagnose the fetal structural malformations, we can do an ultrasound using which we can visualize the fetal morphology, the problem occurs when we have to study the chromosomes of the fetus.

Until not long ago to be able to study the fetal chromosomes, we had to use invasive techniques such as amniocentesis or chorionic villus sampling, which consist in extracting amniotic liquid or chorionic villi, with which we are able to study the fetal chromosomes. These techniques have between a 1-2% abortion risk, which makes it obvious that it isn’t offered to all pregnant women, and only to those which present a high risk of the fetus presenting chromosomopathies.

Nowadays we have a noninvasive prenatal diagnostic test that consists in the detection of fetal DNA in the mothers blood which offers a highly reliable information about the risk of chromosomal abnormalities. This test is based on the fact that during the pregnancy, part of the fetal DNA is found in the mothers blood. This test can be carried out from 9 weeks of pregnancy onwards which is when a sample of the fetal DNA can be found in the mothers blood. This prenatal diagnosis test lets us directly analyze the fetal DNA. It’s a very recent test that has revolutionized the concept of screening anomalies.

This noninvasive prenatal diagnostic test is carried out on the mothers blood presents a very high detection rate, superior to 99,5%, but to interpret these results we have to understand that ‘a low risk result‘ does not discard 100% a chromosomic alteration, but the studies carried out show that the probability of chromosomopathies are more frequent in a higher percentage.

In the case of having a high risk probability, then it’s recommended to carry out an invasive diagnostic testing (amniocentesis or chorionic villus sampling) to confirm the diagnosis.