Non-invasive prenatal testing: what it is, when it is recommended, and what information it provides
Pregnancy monitoring has evolved significantly in recent years thanks to advances in genetics and prenatal diagnosis. Among these, the Non-Invasive Prenatal Test (NIPT) has become a highly useful tool for safely assessing the risk of certain chromosomal abnormalities in the baby, protecting both mother and fetus.
Dr. Carlos de Granda, a specialist in Gynecology and Obstetrics at the Women's Unit of the Ruber International Hospital, explains what this test involves, what information it provides, and what its limitations are.
What is Non-Invasive Prenatal Testing?
During pregnancy, a small amount of DNA from the placenta and fetus naturally circulates in the mother's blood. The Non-Invasive Prenatal Test analyzes this fetal DNA through a simple blood draw from the mother.
It is a safe, quick and risk-free test for pregnancy, as it does not require invasive procedures and poses no danger to the fetus.
It can generally be performed from week 10 of gestation, when the amount of circulating fetal DNA is usually sufficient to obtain reliable results.
What diseases can it detect?
The main objective of the Non-Invasive Prenatal Test is to estimate the risk of the baby having certain chromosomal abnormalities.
Among the most frequent are:
- Down syndrome (trisomy 21).
- Trisomy 18 or Edwards syndrome.
- Trisomy 13 or Patau syndrome.
In addition, many of these studies allow for highly accurate determination of fetal sex and the detection of alterations related to sex chromosomes.
Currently, there are more advanced versions that extend the analysis to other chromosomal abnormalities and certain genetic diseases, although their indication should be assessed on an individual basis.
An important point: it is not a diagnostic test
One of the most important aspects that prospective parents should understand is that the Non-Invasive Prenatal Test does not establish a definitive diagnosis.
This is a screening test that calculates the probability of a certain chromosomal alteration.
Therefore, the results are usually interpreted as:
Low-risk outcome
When the result indicates a low risk, the probability that the baby will present the studied abnormalities is very small.
The main advantage of NIPT is that it offers very high detection rates, higher than those obtained with the classic combined first trimester screening, based on ultrasound and maternal tests.
High-risk outcome
If the result indicates a high risk, it will be necessary to confirm the finding through an invasive diagnostic test, such as amniocentesis or chorionic villus sampling.
These tests allow direct analysis of fetal genetic material and establish a definitive diagnosis.
Does it replace pregnancy ultrasounds?
No. The Non-Invasive Prenatal Test complements, but does not replace, the usual pregnancy check-ups.
Ultrasound scans continue to be essential for assessing fetal growth, the baby's anatomy, and other aspects that cannot be studied through blood tests.
Therefore, prenatal monitoring must combine different diagnostic tools to obtain the most complete information possible about the evolution of the pregnancy.
Which pregnant women should have this test?
The indication for Non-Invasive Prenatal Testing should be assessed on an individual basis during the obstetric consultation.
Factors such as maternal age, personal or family history, first trimester screening results, or the patient's own preferences may influence the recommendation to perform this test.
For this reason, it is essential to receive adequate medical advice before deciding which prenatal screening strategy is most appropriate in each case.
A breakthrough that brings peace of mind during pregnancy
Non-invasive prenatal testing (NIPT) represents one of the greatest advances in fetal medicine in recent years. Through a simple blood test, it provides valuable information about the risk of certain chromosomal abnormalities with high accuracy and without jeopardizing the pregnancy.
At the Women's Unit of the Ruber International Hospital, Dr. Carlos de Granda and his team carry out a personalized assessment of each pregnancy to offer each patient the most appropriate tests and follow-up during this important stage.