Non-Invasive Prenatal Test: Discover Why Thousands of Moms Choose It
The non-invasive prenatal test (NIPT) represents a major breakthrough in prenatal screening, with specificity exceeding 99% for trisomies 13, 18, and 21. Safe and highly effective, this test requires only a simple maternal blood draw, eliminating the risks associated with invasive procedures such as amniocentesis.
In fact, non-invasive prenatal tests can be performed as early as the 10th week of pregnancy, with the optimal window between the 11th and 12th weeks. The sensitivity of NIPT is exceptional: 99% for trisomy 21 (Down syndrome), 98% for trisomy 18 (Edwards syndrome), and 99% for trisomy 13 (Patau syndrome). Moreover, starting July 1, 2024, the Emilia-Romagna region will offer this test free of charge to all pregnant women, regardless of age or risk factors.
In this article, we explore in detail what NIPT is, which conditions it can detect, and why it has become the preferred choice of thousands of expectant mothers in Italy. We will also see how this test identifies chromosomal abnormalities that account for over 70% of known chromosomal disorders, significantly reducing the need for invasive procedures.
What Is the Non-Invasive Prenatal Test (NIPT)?
The NIPT (Non-Invasive Prenatal Test) is an advanced prenatal screening test that analyzes fragments of fetal DNA circulating in the mother’s blood. Through a simple venous blood draw, it assesses the risk that the fetus has certain genetic or chromosomal abnormalities—without any risk to the pregnancy.
How the Fetal DNA Test Works
During pregnancy, small fragments of DNA originating from the placenta—called cell-free fetal DNA (cfDNA)—enter the maternal bloodstream. These fragments closely reflect the fetus’s genetic makeup and can be isolated and analyzed.
The process involves:
- Drawing a blood sample from the pregnant woman
- Extracting circulating cell-free DNA in the laboratory
- Analyzing DNA fragments using next-generation sequencing (NGS) technologies
- Interpreting results to calculate the risk of chromosomal abnormalities
The test measures the proportion of DNA fragments from each chromosome. A normal proportion indicates a low-risk result, while an excess suggests a higher risk of a chromosomal condition.
Screening Test vs Diagnostic Test
It is essential to understand that NIPT is a screening test, not a diagnostic test. It estimates the probability of a condition but does not provide a definitive diagnosis.
- Screening tests identify pregnancies at increased risk
- Diagnostic tests (amniocentesis, chorionic villus sampling) confirm conditions with certainty but carry a miscarriage risk of about 1%
A positive NIPT result must always be confirmed with an invasive diagnostic test. Nonetheless, NIPT is far more accurate than traditional first-trimester screening methods based on ultrasound and blood markers.
When NIPT Can Be Performed
NIPT can be performed from the 10th week of pregnancy onward. Before this point, the amount of fetal DNA in maternal blood may be insufficient, increasing the risk of inconclusive results.
Although fetal DNA can be detected as early as weeks 5–7, a fetal fraction above 4%—usually reached around week 10—is required for reliable analysis. Many experts consider weeks 11–12 the optimal testing window, although NIPT can be performed later if needed.
What Conditions Can NIPT Detect?
Trisomy 21 (Down Syndrome)
Down syndrome, caused by an extra copy of chromosome 21, is the most common chromosomal abnormality detected by NIPT. The test shows 99.7% sensitivity with an exceptionally low false-positive rate of 0.04%, making it highly reliable.
Trisomy 18 (Edwards Syndrome)
Edwards syndrome affects about 1 in 5,500 live births and is associated with severe medical complications. NIPT detects this condition with 98.2% sensitivity and a 0.05% false-positive rate.
Trisomy 13 (Patau Syndrome)
For trisomy 13, NIPT shows 99% sensitivity. While detection accuracy is high, the positive predictive value varies depending on maternal age.
Sex Chromosome Abnormalities
NIPT can also identify conditions involving the X and Y chromosomes, such as:
- Turner syndrome (monosomy X)
- Klinefelter syndrome (XXY)
- Triple X syndrome (XXX)
- Jacobs syndrome (XYY)
Sensitivity remains above 95%, though predictive values vary.
Microdeletions and Extended Panels
Some advanced NIPT tests can detect microdeletions, such as DiGeorge syndrome (22q11.2 deletion). Although sensitivity is lower than for common trisomies, detection remains clinically valuable.
Importantly, any positive NIPT result must be confirmed through invasive diagnostic testing.
Why More and More Mothers Choose NIPT
Complete Safety for Mother and Baby
NIPT involves only a maternal blood draw—no miscarriage risk, no pain, and no fetal complications—making it one of the most reassuring options for expectant parents.
High Accuracy and Very Low False Positives
- Trisomy 21: 99.7% detection, 0.04% false positives
- Trisomy 18: 98.2% detection
- Trisomy 13: 99% detection
False positives are below 0.1%, far lower than traditional screening tests.
Fewer Unnecessary Invasive Procedures
Since the introduction of NIPT, invasive procedures have been reduced by up to 95%, significantly lowering procedure-related miscarriages.
Increasing Accessibility and Free Testing in Some Regions
While NIPT previously cost around €700, access is improving. From July 2024, Emilia-Romagna will provide the test free to all pregnant women, regardless of risk. Sardinia already offers it as primary screening, and other regions are following.
What to Know Before Taking the Test
Importance of Genetic Counseling
Genetic counseling is strongly recommended—especially for high-risk pregnancies or positive results. Counseling is non-directive, meaning parents receive information to make informed decisions aligned with their values.
Diagnostic Confirmation After a Positive Result
Because NIPT is a screening test, positive results must be confirmed with amniocentesis or CVS, guided by a multidisciplinary medical team.
Choosing Between Genome-Wide and Targeted Tests
Some tests analyze the entire genome, while others focus on chromosomes 13, 18, 21, X, and Y. Both approaches are valid when accompanied by proper genetic counseling.
Role of Ultrasound
An ultrasound evaluation, including nuchal translucency measurement, is recommended before NIPT. Certain ultrasound findings may warrant direct diagnostic testing instead.
Conclusion
The non-invasive prenatal test represents a true revolution in modern prenatal care. With exceptional accuracy, complete safety, and early availability, NIPT offers invaluable reassurance to expectant parents while dramatically reducing unnecessary invasive procedures.
While it is not a diagnostic test, when combined with genetic counseling and ultrasound, NIPT empowers families to navigate pregnancy with greater confidence and peace of mind.
As access continues to expand—especially with public funding in some regions—NIPT is becoming a cornerstone of modern prenatal screening. Discuss this option openly with your healthcare provider to determine the best path for your pregnancy.
