What is a non-stress test (NST)?

A non-stress test (NST) is designed to assess fetal well-being by measuring the fetal heart rate in response to fetal movements. The primary goal of the NST is to evaluate how the baby's heart responds when it moves, which indicates adequate oxygen supply and well-being. This test typically involves monitoring the fetal heart rate through external sensors placed on the mother’s abdomen, tracking accelerations in the heart rate corresponding to fetal movements. A healthy response shows that the fetus is active and has a healthy heart rate pattern, suggesting that it is receiving enough oxygen and is not in distress.

Other options describe different assessments that are not the purpose of an NST. For example, measuring fetal growth and evaluating fetal position are part of other examinations and are not specific to the NST. Maternal hormonal levels are also unrelated to this specific test, focusing instead on the fetal response to its environment during late pregnancy.