by David Jackson, MBA
Noninvasive prenatal testing (NIPT) and amniocentesis are two of the most common screening procedures used to determine a baby’s risk of genetic abnormalities. While these terms are often mentioned together, they’re actually two very different tests.
What is NIPT?
NIPT is a simple blood test that’s typically recommended during the first trimester of pregnancy. It’s a safe and effective way to determine the likelihood of chromosome abnormalities like Down syndrome, Edwards syndrome, and Patau syndrome.
During NIPT, your OB/GYN or general practitioner draws a sample of your blood. They send your sample to a laboratory that analyzes it for cell-free DNA (cfDNA). Cell-free DNA is released into your bloodstream by the placenta.
NIPT is a screening test. Instead of diagnosing a specific condition, it determines if your baby has a high or low risk of a chromosomal disorder.
What is Amniocentesis?
Amniocentesis is a prenatal screening that typically occurs during the second trimester of your pregnancy, sometime after week 15.
During amniocentesis, your OB/GYN or general practitioner uses a long, thin needle to extract a sample of amniotic fluid from your uterus. Amniotic fluid surrounds your womb and contains some of your growing baby’s cells. Your provider sends your sample to a laboratory that tests it for certain genetic disorders, including Down syndrome, cystic fibrosis, and spina bifida.
Amniocentesis is a diagnostic test. This means it can determine with certainty if your baby is at risk of a chromosome disorder.
Who Can Benefit From NIPT or Amniocentesis?
Anyone who is pregnant can benefit from NIPT or amniocentesis. These screening procedures can help you better plan for the future and provide peace of mind.
Undergoing either test is a matter of personal preference. However, your OB/GYN or general practitioner may encourage you to take action if:
- You’re 35 or older
- You have a personal or family history of chromosome abnormalities
- Your mother or father has a chromosome abnormality
Your provider might also recommend amniocentesis if they suspect your baby has an infection or anemia.
How Do I Interpret My Test Results?
How you interpret your test results depends on the type of screening you underwent.
NIPT
When analyzing NIPT results, the laboratory assesses the percentage of cfDNA in each chromosome. If your test falls within the standard range, you receive a “negative” result, meaning your baby is at a decreased risk of developing certain chromosome abnormalities.
If your test is outside of the standard range, you might receive a “positive” result. This means your baby is at an increased risk of developing certain chromosomal abnormalities. Even so, NIPT isn’t 100% conclusive. Your OB/GYN or general practitioner can order additional diagnostic tests to determine your baby’s risk.
Amniocentesis
If the results of your amniocentesis test are normal, there’s very little risk of your baby having a chromosome abnormality.
If your results are abnormal, it means there’s a good chance that your baby is at risk. But the results aren’t 100%. Your OB/GYN or general practitioner can order additional tests to gather more information.
The type of prenatal testing that’s right for you depends on your age, health history, and personal preference. Following an in-office consultation and physical exam, your OB/GYN or general practitioner can make recommendations that align with your needs.