A nonstress test (NST), also known as fetal heart rate monitoring, is a common prenatal test used to check on a baby's health. During a nonstress test a baby's heart rate is monitored to see how it responds to the baby's movements. The term nonstress refers to the fact that nothing is done to place stress on the fetus during the test.
Typically, a nonstress test is recommended when it's believed that the fetus is at increased risk of death. A nonstress test may be done after 26 to 28 weeks of pregnancy. Certain nonstress test results might indicate that you and your baby need further monitoring, testing or special care.
A nonstress test is a noninvasive test that doesn't pose any physical risks to you or your baby.