What is the purpose of a non-stress test (NST)?

A non-stress test (NST) is specifically designed to assess fetal well-being by monitoring the fetal heart rate and its patterns in response to fetal movements. During the test, external monitors are attached to the mother’s abdomen to track the fetal heart rate and movements over a designated period, usually 20 to 40 minutes. An effective NST is indicated by a heart rate that shows variability in response to movements, reflecting that the fetus is receiving adequate oxygen and is not in distress. This relationship between fetal movements and heart rate patterns provides crucial information about the fetus's health, making the assessment of these patterns the primary purpose of an NST.

Other options focus on different aspects of pregnancy monitoring. While evaluating uterine contractions, placental function, and maternal blood volume are also important in maternity care, they are not the specific focus of a non-stress test. The NST's main intent is to ensure that the fetus is thriving, particularly in high-risk situations or when there are concerns about prenatal health.