Non-Invasive Prenatal Testing (NIPT) is a prenatal screening test that estimates the likelihood of certain chromosomal abnormalities in the fetus. It analyzes cell-free fetal DNA (cfDNA) circulating in the mother’s blood and can be performed from 10 weeks of pregnancy onwards.
Unlike invasive diagnostic procedures such as amniocentesis and chorionic villus sampling (CVS), which require sampling of amniotic fluid or placental tissue, NIPT requires only a maternal blood sample and poses no procedure-related risk of miscarriage.
One such option is LifeCell Diagnostics’ NIPT (All Chromosomes), which offers comprehensive screening for chromosomal abnormalities using a maternal blood sample. Understanding what NIPT screens for, its benefits, and its limitations can help expectant parents make an informed decision in consultation with their healthcare provider.
What is an NIPT Test?
Non-Invasive Prenatal Testing (NIPT), also known as cell-free DNA (cfDNA) screening, is a prenatal screening test that analyzes cell-free DNA in a maternal blood sample. Most of this fetal DNA originates from the placenta and closely reflects the fetus’s genetic makeup.
The NIPT test is extremely accurate in the diagnosis of Trisomy 21, Trisomy 18, and Trisomy 13; these are related to Down’s Syndrome, Edwards’ Syndrome, and Patau’s Syndrome, respectively. The Society for Maternal Fetal Medicine states that the cell-free DNA test is the most accurate test for these three syndromes.
Reasons for a Pregnant Woman to Consider NIPT
- It can be performed early in pregnancy
Testing through cell-free DNA can usually be done after the 10th week of pregnancy. This indicates that the chances of certain chromosomal abnormalities can be made known relatively early, enabling further discussion about the results and future plans with healthcare providers.
- It performs well for common Trisomies
The NIPT screening test is notably excellent for the detection of Trisomy 21, 18, and 13. As per the recommendations by the SMFM, cell-free DNA is the most sensitive and specific screening test available for these frequent Trisomies. The NHS also includes screening for Down’s Syndrome, Edwards’ Syndrome and Patau’s syndrome as part of antenatal screening.
Nevertheless, high sensitivity and specificity do not imply diagnosis. It is important to note that even though highly accurate tests may have false-positive and false-negative outcomes.
- Maternal age is not the only deciding factor
Down syndrome is one of several chromosomal conditions whose chances of occurring increase with maternal age; however, age criteria are not being used as restrictions for prenatal screening based on professional recommendations. There should not be any age or risk criteria for prenatal screening.
That means even a young woman who is pregnant without any risk factors can go through the NIPT Test to reassure herself.
What Does a High-Risk NIPT Result Mean?
It doesn’t necessarily mean that the baby has a chromosomal condition..
A high-risk or positive test result only indicates the presence of an increased chance that the pregnancy will have the chromosomal anomaly. The result is not conclusive of the presence of the anomaly in the fetus. Screening tests may sometimes give either false-positive or false-negative results, which should be understood correctly.
According to the American College of Obstetricians and Gynecologists (ACOG), individuals with a high-risk NIPT result should receive genetic counselling and be offered a comprehensive ultrasound evaluation along with confirmatory diagnostic testing, such as chorionic villus sampling (CVS) or amniocentesis.
Thus, a positive NIPT test should be discussed with a healthcare provider to determine the most appropriate next steps.
Do All NIPT Tests Screen for the Same Conditions?
No. The conditions screened depend on the NIPT panel selected.
While all standard NIPT panels screen for Trisomy 21, Trisomy 18, and Trisomy 13, expanded panels may also screen for sex chromosome aneuploidies, abnormalities involving other chromosomes, selected microdeletions, and other clinically relevant genetic conditions.
LifeCell Diagnostics’ NIPT (All Chromosomes) is an expanded NIPT panel, trusted by healthcare professionals, that screens for the most common fetal chromosomal abnormalities, including Trisomy 21 (Down syndrome), Trisomy 18, Trisomy 13, Turner syndrome, other sex chromosome aneuploidies (XXX, XXY, XYY), and rare autosomal aneuploidies.
Can NIPT Replace an Ultrasound Scan?
NIPT tests cannot substitute for pregnancy ultrasounds, since the two tests offer distinct sets of information.
Chromosomal defects are screened by cell-free DNA testing, but ultrasound is employed to assess the structural anomalies of a foetus. Structural anomalies may arise both in pregnancies affected by chromosomal anomalies and those free from them.
According to ACOG guidelines, all pregnant women must be advised to undergo a second-trimester ultrasound test for structural anomalies of the foetus at 18-22 weeks of pregnancy. Ultrasound tests are also considered a necessary part of antenatal screening according to the NHS.
A negative NIPT test result, however, does not exempt a pregnant woman from further recommended ultrasounds.
What Should Be Considered Before Choosing NIPT?
Prior to getting the NIPT Test, it is essential to be familiar with the list of conditions the particular panel can screen and what the result will realistically demonstrate.
It is important to keep in mind what one might do following the receipt of the result showing a higher risk of chromosomal abnormalities, since the positive result can lead to further procedures such as genetic counselling, ultrasound, and the analysis of the CVS and amniotic fluid.
Experts recommend that during prenatal genetic tests, individuals should be provided with information on the advantages and disadvantages of the procedure.
Conclusion
NIPT is an essential form of prenatal testing, which can evaluate the probability of having common forms of chromosomal abnormalities, such as Trisomy 21, 18, and 13. As it was recently stated in the medical literature, cell-free DNA testing needs to be provided to all pregnant women and not only to patients with advanced maternal age or high-risk pregnancies.
Knowing the goals, limitations, and boundaries of the NIPT Test, and then talking to an obstetrician or a genetic counsellor can enable a woman to choose the appropriate prenatal test.
