Noninvasive Prenatal Testing

What is noninvasive prenatal testing?

Noninvasive Prenatal Screening or Testing, also called NIPS or NIPT, is a blood test during pregnancy that screens for Down syndrome (also called trisomy 21), trisomy 13, and trisomy 18. It also screens for conditions caused by extra or missing sex chromosomes, such as Turner syndrome. NIPT can be drawn as early as 10 weeks gestation and results generally take one to two weeks to return.

Though NIPT has a high detection rate for certain conditions, it is not 100% accurate and cannot provide a diagnosis. NIPT can only estimate whether the risk of the pregnancy having certain conditions is increased or decreased.

What are the possible results from NIPT?
  • Negative/Low-Risk: A negative or low-risk result means that it is very unlikely the pregnancy has one of the conditions NIPT screens for. It is important to remember that this test is not 100% accurate and does not screen for all genetic conditions.
  • Positive/High-Risk: A positive or high-risk result means the pregnancy is at increased risk for a particular condition. The chance for a true positive result can vary and be influenced by the presence of any birth defects, age of the pregnant person, and how often the condition typically occurs. However, only diagnostic testing can give a definite answer. Genetic counseling is recommended to discuss positive/high-risk results and additional testing options.
  • No Result/Inconclusive: There is a small possibility that results may not be reportable or may be inconclusive. In these cases, your health care provider may recommend you have your blood redrawn, have different testing, or have genetic counseling to discuss your options.

Diagnostic testing is available and can provide a “yes” or “no” answer regarding chromosome conditions during the pregnancy. There are two options: chorionic villus sampling (CVS) and amniocentesis. Both diagnostic procedures are performed by an experienced specialist because they are invasive procedures that involve less than 1% risk of complications and/or miscarriage.

You also have the option to decline all prenatal testing. Regardless of your testing decision, ultrasound can be performed to look for birth defects and markers for genetic conditions. Ultrasound alone cannot rule out all birth defects or genetic conditions.

Talking to a genetic counselor may be beneficial to learn more about genetic testing options in pregnancy and help you decide on a personal screening plan. To schedule an appointment with a genetic counselor, please call our scheduling team at 713-486-9302.