The key difference between NIPT and amniocentesis is that NIPT (Non-invasive prenatal testing) is performed by using cell-free fetal DNA circulating in maternal blood, while amniocentesis is performed by using the amniotic fluid during pregnancy.
NIPT and amniocentesis are two techniques used in prenatal diagnosis. Prenatal diagnosis refers to diagnosis before birth. Therefore, there are several tests involved in prenatal diagnosis. These tests help doctors to see if there are any developing problems in the baby. These tests help to find genetic disorders before birth.
CONTENTS
1. Overview and Key Difference
2. What is NIPT
3. What is Amniocentesis
4. Similarities – NIPT and Amniocentesis
5. NIPT vs Amniocentesis in Tabular Form
6. Summary – NIPT vs Amniocentesis
What is NIPT?
Non-invasive prenatal testing (NIPT) is a prenatal diagnosis technique performed using the cell-free fetal DNA or bits of baby’s DNA circulating in the maternal blood. This method is highly used to determine the risk of the baby being born with certain chromosomal abnormalities such as trisomy 21, trisomy 18, and trisomy 13. In this testing, small DNA fragments that circulate in the blood of a pregnant woman are tested. Generally, most DNA fragments are found in the nucleus of the cell. But, DNA fragments used for NIPT are free floating in mothers’ blood. Therefore, they are also known as cell-free fetal DNA (cffDNA).
Cell-free fetal DNA fragments contain less than 200 DNA base pairs and arise when the cell is dead and the contents of the cell are released into the bloodstream. Moreover, cell-free fetal DNA derives from placental cells and is usually identical to fetal DNA. Therefore, the analysis of cffDNA from the placenta provides the opportunity for early diagnosis of certain genetic abnormalities without harming the fetus. Furthermore, NIPT can determine the paternity and fetal sex earlier in gestation. In addition, it is also used to verify fetal Rhesus D, preventing mothers who are Rhesus D negative from undergoing unnecessary prophylactic treatment.
What is Amniocentesis?
Amniocentesis is a prenatal diagnosis technique performed using the amniotic fluid that surrounds and protects the baby during pregnancy. This test is generally used in prenatal diagnosis of chromosomal abnormalities, fetal infections, and sex determination. In amniocentesis, a small amount of amniotic fluid that contains fetal tissues is taken from the amniotic sac surrounding the developing fetus. Fetal DNA is later examined for genetic abnormalities.
Figure 01: Amniocentesis
Amniocentesis is performed on women between 15 to 20 weeks in gestation. Women who are chosen for this test are primarily at increased risk for genetic and chromosomal problems. As this test is invasive, it carries a small risk of miscarriage. Furthermore, this procedure can be used for prenatal sex discernment. Therefore, this procedure has restrictions in some countries.
What are the Similarities Between NIPT and Amniocentesis?
- NIPT and amniocentesis are two techniques used in prenatal diagnosis.
- Both techniques can be used to diagnose chromosomal abnormalities and sex discernment.
- Both techniques are used for women who are at an increased risk of giving birth to babies having genetic disorders.
- Fetal DNA fragments are checked in both techniques.
- They are performed by skilled technicians.
What is the Difference Between NIPT and Amniocentesis?
NIPT is a prenatal diagnosis technique performed using the baby’s DNA circulating in the maternal blood, while amniocentesis is a prenatal diagnosis technique performed using the amniotic fluid surrounding and protecting the baby during pregnancy. Thus, this is the key difference between NIPT and amniocentesis. Furthermore, NIPT is performed anytime after 9 weeks into the pregnancy, while amniocentesis is performed when a woman is between 15 to 20 weeks in gestation.
The below infographic presents the differences between NIPT and amniocentesis in tabular form for side-by-side comparison.
Summary – NIPT vs Amniocentesis
NIPT and amniocentesis are two techniques used in prenatal diagnosis. Both techniques analyze fetal DNA in their procedure. NIPT is performed using the baby’s DNA in the placenta, while amniocentesis is performed by using the amniotic fluid that surrounds and protects the baby during pregnancy. So, this is the key difference between NIPT and amniocentesis.
Reference:
1. Norwitz, Errol R, and Brynn Levy. “Noninvasive Prenatal Testing: The Future Is Now.” Reviews in Obstetrics & Gynecology, MedReviews, LLC, 2013.
2. “Amniocentesis.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 12 Nov. 2020.
Image Courtesy:
1. “Amniocentesis” By BruceBlaus – Own work (CC BY-SA 4.0) via Commons Wikimedia