NIPT (Non-Invasive Prenatal Testing): Introduction, Pregnancy Screening, Antenatal tests, Prenatal Test

Table of Contents

What is NIPT?

NIPT (Non-Invasive Prenatal Testing) is a prenatal blood test that is performed beginning around 10^th weeks of pregnancy and can screen certain genetic conditions. It can be performed at any time after the 10^th week of pregnancy. However, the ideal time is upto the 24^th week.

How does NIPT work?

Our blood contains fragments of DNA known as Cell-free fetal DNA (cffDNA). It is fetal DNA that originates from placental trophoblasts that are approximately 200 base pairs (bp) in length which freely circulates in the maternal blood. When a woman is pregnant, her blood will also contain DNA fragments from the placenta, which has a genetic makeup that is usually identical to that of a developing baby. By analyzing this DNA in a mother’s blood, it can be determined if there is an increase or decrease of certain genetic conditions.

What condition does NIPT screen for?

Though this test began screening for the most common syndromes, over time the list of conditions being screened has grown. Today, in addition to Down syndrome (Trisomy 21, T21), NIPT also screens for Trisomy 18 (Edwards syndrome), Trisomy 13 (Patau syndrome), and sex chromosome aneuploidies (SCAs). And in some cases, also the other chromosome conditions as well. The effect of screened conditions varies tremendously from very mild to very severe.

These conditions usually don’t run in families and with every pregnancy there is some chance of one of these conditions. The chance that a pregnancy is affected with a condition depends on a number of factors including maternal age. Women of any age can have a baby with one of these conditions.

Fig: NIPT (Non-Invasive Prenatal Testing)

What can NIPT talk about?

It is a screening test that can determine if the chance of a certain genetic condition in a pregnancy is higher or lower. Since NIPT is a screening test, not a diagnostic test, it cannot give a yes or no answer. If results indicate high or increased chance, then diagnostic tests such as amniocentesis can be performed if the patient desires to determine whether the baby has the condition or not.
Amniocentesis, however, has a 0.3% chance of miscarriage, which is why not all women who are found to be high risk choose to pursue it. If the NIPT result indicates a low or decreased chance, the likelihood the baby has the condition is lower but not zero. False positive or false negative can occur with NIPT. The chance of false positive or false negative result depends on condition tested for.

How does NIPT compare to the first Trimester screening (FTS) test?

Both NIPT and FTS test are performed for screening Down syndrome (DS). The two tests, however, have different strengths and limitations.
FTS involves analyzing maternal blood for protein markers as well as an ultrasound. This first trimester ultrasound involves measuring a pocket of fluid at the back of the baby’s neck. This measurement is also known as nuchal translucency (NT).
Just like NIPT, FTS provides information regarding the chance of DS, T-18, T-13. In addition to these conditions, ultrasound measurements taken during FTS can also provide information that may suggest the possibility of other genetic conditions as well as provide early screening for some birth defects, including certain heart defects and neural tube defects. Although FTS may provide information for a greater number of conditions, NIPT is more accurate for DS.
The DNA analyzed in NIPT is placental in origin, so discrepancies between the baby’s DNA and that of the placenta can occur. There is no prenatal genetic screen that tests for everything. Even when the results of NIPT or FTS indicate a low likelihood. There is a very small chance of genetic conditions or birth defects.
If one decides to undergo prenatal genetic testing, your healthcare provider can help decide which prenatal provider and which testing will be best for your specific situation.
Testing will be influenced by factors such as maternal age, gestational age, past medical history, and family history. These should be provided to your doctor.
Since NIPT and FTS cannot provide a definitive result, they give a more accurate answer compared to amniocentesis. Tests such as amniocentesis are much more invasive.

Who should get NIPT?

It is an available screening regardless of age or risk. NIPT must be done for pregnant women regardless of age or risk (even for a 35+ year old). It should be done for:

Mom-to-be who has had a child with a chromosomal disorder.
Previously who had a child with a genetic disorder.

NIPT should be avoided for women:

With multiple pregnancies-greater than the twins.
With history of cancer.
Undergone blood transfusion in the last three months.

Reliable NIPT Screening:

NIPT is the next-generation sequencing(NGS) technology. NGS provides a very low false positive rate compared to other methods.
NGS has significantly fewer false positives for chromosomal abnormalities than other screening methods.
NIPT helps deliver more accurate results in screening. Molecular analysis with NIPT can detect certain chromosomal conditions more reliably than with other methods.
It can detect issues such as fetal chromosomal diseases, including extra or missing chromosomal material (aneuploidy), caused by the presence of an extra chromosome copy (e.g., trisomy) or missing copy (monosomy).
There are no complications or risks associated with NIPT. The screening is completely non-invasive and safe for all.

References:

Jayashankar, S.S., Nasaruddin, M.L., Hassan, M.F., Dasrilsyah, R.A., Shafiee, M.N., Ismail, N.A.S. and Alias, E., 2023. Non-invasive prenatal testing (NIPT): reliability, challenges, and future directions. Diagnostics, 13(15), p.2570.
van Prooyen Schuurman, L., de Koning, H.J., Meier, E., Galjaard, R.J.H. and van Ravesteyn, N.T., 2025. Clinical and economic impact of genome-wide non-invasive prenatal testing (NIPT) as a first-tier screening method compared to targeted NIPT and first-trimester combined testing: A modeling study. PLoS Medicine, 22(11), p.e1004790.
Marton, T., Erdélyi, Z.R., Takai, M., Mészáros, B., Supák, D., Ács, N., Kukor, Z., Herold, Z., Hargitai, B. and Valent, S., 2025. Systematic review of accuracy differences in NIPT methods for common aneuploidy screening. Journal of Clinical Medicine, 14(8), p.2813.
Garg, R.K., Kumar, Y., Niwas, R. and Singh, J., 2025. Non-Invasive Prenatal Testing (NIPT): A Paradigm Shift in Prenatal Care. International Journal of Preventive Medicine, 16, p.86.
Norwitz, E.R. and Levy, B., 2013. Noninvasive prenatal testing: the future is now. Reviews in obstetrics and gynecology, 6(2), p.48.
Allyse, M., Minear, M.A., Berson, E., Sridhar, S., Rote, M., Hung, A. and Chandrasekharan, S., 2015. Non-invasive prenatal testing: a review of international implementation and challenges. International journal of women’s health, pp.113-126.