What is a nonstress test (NST) and its purpose during pregnancy?

A nonstress test (NST) is a critical assessment used in prenatal care to evaluate fetal well-being. The primary purpose of the NST is to measure the fetal heart rate in relation to fetal movements. During the test, the healthcare provider monitors the heart rate of the fetus using a Doppler instrument while the mother is encouraged to use a button to indicate when she feels fetal movements. An optimal response reveals that the fetal heart rate increases with movements, which is a sign of a healthy, well-oxygenated baby.

The significance of this test lies in its ability to detect potential issues in the fetal condition, such as fetal distress or other complications that may arise, particularly in high-risk pregnancies. A reactive NST, characterized by an increase in the fetal heart rate following movements, typically indicates that the fetus is handling the stresses of pregnancy well.

Therefore, the choice indicating that the NST measures fetal heart rate in response to movements correctly reflects the primary function and purpose of this test within antepartum care.