What Is the Best Alternative to Amniocentesis?
Amniocentesis is an invasive prenatal diagnostic test that involves extracting a small amount of amniotic fluid via abdominal puncture. It is performed to detect chromosomal abnormalities, genetic diseases, and neural tube defects in the fetus. Although it is highly accurate, being an invasive test, it carries a small risk of complications, including miscarriage (approximately 0,1%–0,3% according to the American College of Obstetricians and Gynecologists, ACOG).
Given the severity of the risks, less invasive alternatives to amniocentesis have been developed.
What Is the Best Alternative to Amniocentesis?
The non-invasive prenatal test (NIPT) analyzes fetal DNA present in maternal blood to predict the risk of chromosomal abnormalities, such as Down syndrome or Edwards syndrome. With an accuracy greater than 99%, it is considered the best alternative to amniocentesis for detecting chromosomal abnormalities.
Fetal DNA can be detected in maternal circulation starting from week 9 of pregnancy, thus the test can be reliably performed from week 10 onwards.
There are also other non-invasive alternatives used in prenatal screening, such as nuchal translucency ultrasound and the double, triple, or quadruple blood screening tests, which combine maternal blood analysis with ultrasound monitoring to calculate the risk of abnormalities. These tests do not confirm the diagnosis but may indicate the need for a more precise test.
Differences Between NIPT and Amniocentesis
- Type of Test: Amniocentesis is an invasive test that requires the extraction of a sample of amniotic fluid by means of an abdominal puncture. In contrast, the NIPT is a non-invasive screening test that only requires a blood draw from the mother.
- Accuracy: Both tests offer high sensitivity. However, since the NIPT is a screening test, should an abnormality be detected, an invasive test must be performed to confirm the findings.
- Risk to Pregnancy: Amniocentesis carries a risk of miscarriage between 0,1% and 0,3%. In contrast, the NIPT poses no miscarriage risk, as it is not invasive.
- Timing: The NIPT can be performed with high accuracy from week 10 onwards. Amniocentesis is performed starting at week 16.
When Is Amniocentesis Instead of NIPT Recommended?
- To confirm a diagnosis following a high-risk NIPT result.
- In cases of suspected hereditary genetic disease that can only be confirmed by analyzing amniotic fluid.
- If fetal malformations are detected during prenatal ultrasound.
- When the parents are carriers of a chromosomal abnormality, or there is a family history of genetic anomalies.
What Should Be Done If the NIPT Indicates High Risk?
A high-risk result does not confirm an abnormality but it indicates the need for an amniocentesis or chorionic villus sampling (CVS) for a definitive diagnosis. The choice of the appropriate test should be made with the support of a specialized medical team.