Non-invasive prenatal testing (NIPT) was invented by Dennis Lo, widely regarded as the father of non-invasive prenatal testing. The mass application of the test began in late 2011 in several countries. Dennis’ research on cell-free DNA of fetuses birthed NIPT.

Non-invasive prenatal testing (NIPT) is a test for pregnant women in their first trimester to determine whether the fetus has the probability of being affected by genetic disorders. It is a screening tool consisting of some more tests and ultrasound until 15-16 weeks of pregnancy for a final verdict.

NIPT is a valuable test for the mothers-to-be to provide efficient and cost-effective early diagnosis of genetic disorders. The NIPT market is one of the fastest evolving markets in other prenatal testing industries. The global non-invasive prenatal market was valued at $2.52 billion in 2020 and is expected to reach $12.61 billion by 2031.

What is Non-Invasive Prenatal Testing?

Non-invasive prenatal screening involves screening the fetus to check if the developing baby is likely to be affected by genetic abnormalities. A small amount of fetal DNA passes through into the mother's bloodstream during pregnancy, allowing for testing that does not involve surgical removal of amniotic cells, needle sampling of tissue, or taking a sample of umbilical cord blood.

Thus, NIPT involves testing the passed deoxyribonucleic acid (DNA) of the baby to determine the probability of the unborn child having genetic abnormalities.

Generally, after ten weeks of pregnancy, every obstetrician-gynecologist (ob-gyn) stresses on the subject for being well-informed regarding the health condition of the developing fetus. Generally, genetic disorders are more common in older mothers’ babies (above 30-35 years).

Mainly, the non-invasive prenatal testing tests the following genetic abnormalities in the growing fetus (in the first trimester):

● Down Syndrome (trisomy 21)
● Edwards Syndrome (trisomy 18)
● Patau Syndrome (trisomy 13)
● Genetic abnormalities due to missing or extra chromosomes (either X or Y or both)

The genetic information of the fetus that is taken from the mother’s bloodstream undergoes all the above tests. NIPT is particularly sensitive to trisomy 21 (Down Syndrome).

Why is it needed?

NIPT is a non-invasive prenatal screening test. It is 99% accurate in detecting common chromosomal abnormalities, but NIPT should still be considered a screening method as opposed to a diagnostic one.

While it is not necessary to do the NIPT test, it is helpful to perform the test because:

● It is a simple blood test with no harm to the baby and can be conducted easily.
● NIPT quickly detects the presence of genetic abnormalities at the early stages.
● It helps the parents to take time and decide the next step.

Doctors usually advise the expecting mothers to opt for diagnostic tests (such as chorionic villus sampling (CVS) and amniocentesis) to confirm the NIPT results.

A NIPT screening can be done if:

● The mother has performed a combined trimester test to check the risk of developing genetic abnormalities by the fetus and is found to be at high risk.
● The mother has already missed her trimester check-up of screening or diagnosis.
● Before going for a diagnostic test, the expecting parents want to take the NIPT for confirmation.
● You either carry a risk of miscarriage or have already given birth to a baby with genetic abnormalities priorly

NIPT screening also becomes essential for all those who satisfy either of the following criteria of risk factors:

● There is a family history of chromosomal abnormalities.
● The mother, father, or both have been tested to be genetic carriers of a disorder.
● The mother is pregnant at 35 years or older.

While these risk factors are not guaranteed to harbor genetic disorders, taking the NIPT screening for better planning is always best.

How is it Done?

Even though the test has a high accuracy rate, it is only a screening and not a fair diagnostic test. Therefore, fathom the next steps only after taking and analyzing a structured diagnostic test (as per the consultation of a doctor).

In NIPT, a simple maternal blood draw is combined with an ultrasound. Later on, the labs analyze the sample via the cfDNA in the mother’s bloodstream (cfDNA is the cell-free DNA of the fetus that escapes into the mother’s blood during pregnancy).

The results will then be formulated and propagated. If the result is inconclusive, and the amount of cfDNA is not enough to evaluate the results. It might require re-drawing of blood for a test after increased gestation.

NIPT Pros and Cons to Consider

While NIPT is undoubtedly a useful and must-to-do test for all pregnant women in their first trimester, it still comes with a set of pros and cons to consider.

Therefore, before performing the test, the expecting parents should have a detailed discussion about non-invasive prenatal testing.

Pros of NIPT are:

● The test can be done quite earlier at the stage of 10 weeks of pregnancy.
● It has a low false-positive rate and shows high sensitivity to chromosomal diseases.
● The number of unnecessary diagnostic tests (like CVS and amniocentesis) has also dramatically reduced since the advent of NIPT in 2011-12.
● NIPT screening includes ultrasound and two simple blood tests, making it a simpler choice.
● Even though CVS and amniocentesis are confirmatory tests with accurate results, it comes with a small risk of miscarriage. Therefore, NIPT is quite safer for the baby.

Cons of NIPT are:

● It cannot predict or diagnose the atypical genetic disorder. Therefore, its reach is limited to chromosomal disorders.
● NIPT screening started merely a decade ago; it is new, and hence, further evaluation is required to explore its depths.
● A negative result does not guarantee a healthy fetus.
● Some parents perform NIPT solely to know the sex of the baby.

NIPT Results: What to Expect?

It takes about two weeks to receive a confirmed NIPT result. As per the mechanism of NIPT, if the results turn out to be positive, it means that the fetus has a high chance of being born with a genetic abnormality. However, if the outcome is negative, the baby is probably safe.

When one receives an abnormal NIPT result, one must discuss it with your ob-gyn and genetic counselors. A NIPT is a test designed to screen for chromosomal issues in unborn babies. It's becoming more widely accepted as the standard for prenatal screening due to its high accuracy rate. These tests sometimes reveal abnormalities that could not otherwise be detected without invasive procedures.