Pregnancy Information Center

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Your Guide to Prenatal Tests

Fetal Nonstress Test (NST)

Fetal Nonstress Test (NST)

When it’s done: After 28 weeks

Your doctor may order this test if you don’t feel your baby kick often or have a high-risk pregnancy. For this test, a special belt is placed around your abdomen to measure the baby’s heart rate in response to its own movements. An NST is often performed biweekly in high-risk pregnancies.

Sometimes an NST is done along with an ultrasound to assess the health of an unborn baby. These tests together are called a biophysical profile or BPP and can determine if the baby should be delivered early. It can take up to 20 minutes to perform a BPP. 

Attribution: joruba/iStock/Thinkstock
By Jenilee Matz, MPH. Published on May 6, 2013. Jenilee is a medical writer, health educator and triathlete based in Charlotte, NC. Updated on December 30, 2015.
Reviewed by Elisabeth Aron, MD, MPH, FACOG on September 27, 2015.