Non-invasive prenatal testing: Purpose, advantages, risks and limitations of NIPT

In an interview with HT Lifestyle, Dr Chetna Jain, Director Dept of Obstetrics and Gynecology at Cloudnine Group of Hospitals in Gurgaon Sector 14, gushed, “NIPT/NIPS has revolutionised the care of pregnant women. It analyses cell free fetal DNA which is circulating in mother’s blood. This test can be done from 10 weeks of pregnancy. Traditionally, double markers were used as a screening test for Down syndrome between 11 to 13 weeks of pregnancy as first trimester serum (blood) screening. It has a detection rate of about 80%. When combined with nuchal scan, the detection rates are about 90% with a 5% false positive. This means about 5 % women will test positive even if their baby is normal and would need further invasive testing. Quadruple marker is a second trimester screening test for Down syndrome. It is performed between 15 to 22 weeks. It has a detection rate of 80% for Down syndrome with 5% false positive.”

Purpose:

Dr Chetna Jain revealed that NIPT/NIPS is primarily used to display for frequent chromosomal circumstances within the fetus, significantly –

1. Trisomy 21 (Down syndrome): This is attributable to an additional copy of chromosome 21.
2. Trisomy 18 (Edwards syndrome): This is attributable to an additional copy of chromosome 18.
3. Trisomy 13 (Patau syndrome): This is attributable to an additional copy of chromosome 13.
4. Sex chromosome abnormalities: NIPT/NIPS also can display for circumstances similar to Turner syndrome (monosomy X) or Klinefelter syndrome (XXY).

How It Works:

Dr Chetna Jain shared, “During pregnancy, a small amount of fetal DNA is naturally released into the pregnant women’s bloodstream. NIPT/NIPS uses a maternal blood sample to isolate and analyze this fetal DNA. By examining the relative amounts of different chromosomes or specific genetic markers, the test can estimate the risk of certain chromosomal abnormalities.”

Advantages:

• Non-invasive: NIPT/NIPS doesn’t pose any threat of miscarriage as a result of it solely requires a blood pattern from the pregnant individual.
• High Accuracy: NIPT/NIPS has a excessive detection fee for frequent chromosomal circumstances, significantly Down syndrome, with decrease false-positive charges in comparison with conventional screening checks like maternal serum screening (e.g., quad display).
• Early Detection: NIPT/NIPS may be carried out as early as 9-10 weeks of being pregnant, offering earlier outcomes in comparison with different diagnostic checks like amniocentesis or chorionic villus sampling (CVS).

How correct is NIPT/NIPS?

Dr Chetna Jain answered, “NIPT is highly accurate. The detection rate of Down syndrome is 99%, 96% for Trisomy 18 and 91% for Trisomy 13. NIPT has highest detection achieved by any noninvasive test. A combined assessment with ultrasound and an NIPT significantly reduces the need for invasive procedures like Amniocentesis.” She elaborated –

• False constructive NIPT: The accuracy of NIPT is 99% for Down syndrome. The probabilities for false constructive is uncommon. More information is required to cite actual figures.
• False unfavourable NIPT could be very uncommon, about 0.02% to 0.2% in detecting autosomal chromosomal circumstances like Down syndrome.

Risks related to NIPT:

According to Dr Chetna Jain, NIPT has zero threat of miscarriage. CVS process has a miscarriage threat of 0.5 to 1%. Amniocentesis has a miscarriage threat of 0.25 to 0.5%.

Limitations and concerns of NIPT:

• NIPT has decreased sensitivity for twin being pregnant. It isn’t accessible for triplets or larger order a number of pregnancies.
• It isn’t accessible for different genetic circumstances like cystic fibrosis.
  It may give false constructive or false unfavourable outcomes.
• It isn’t accessible for ladies who themselves have Down syndrome, balanced chromosomal translocations or most cancers.
• Women with organ transplant or blood transfusion in final 4 months can not do it.
  NIPT can not display for all chromosomal circumstances. Not all NIPT panels display for circumstances associated to intercourse chromosomes like Turners, Klinefelter and Triple X syndrome.
• Since NIPT is a screening check, for all constructive instances a diagnostic check is beneficial for affirmation which is CVS or Amniocentesis. A being pregnant cannot be terminated primarily based on a display constructive NIPT end result.

Who ought to do NIPT?

Dr Chetna Jain knowledgeable, “NIPT is offered to all pregnant women from 10 wks in the USA, even to low risk population. It should be offered and considered by women where maternal age is > 35 years, ultrasound shows abnormal findings, or there is a family or personal history of chromosomal abnormality.”

Limitations:

• Any pregnant ladies present process NIPT ought to perceive that although that is one of the best screening check accessible so far, it will possibly have false positives and false negatives. Any irregular end result would require an extra invasive testing by Amniocentesis or CVS.
• It is vital for potential dad and mom in early being pregnant to have sufficient data on NIPT. With advances in know-how, in future extra circumstances can be recognized by noninvasive testing. As of right now, NIPT is having a wonderful triumph above all noninvasive screening checks.

Considerations:

• NIPT/NIPS outcomes must be interpreted by a professional healthcare supplier who can focus on the implications of constructive or irregular findings and information additional diagnostic testing if vital.
• NIPT/NIPS is non-obligatory and is obtainable to pregnant people primarily based on their private preferences and threat components.

In abstract, NIPT/NIPS is a helpful prenatal screening instrument that gives non-invasive evaluation of fetal genetic threat for frequent chromosomal circumstances throughout being pregnant. It offers early and correct data that may information subsequent prenatal care and decision-making.