What is a non-stress test?

A non-stress test is a fetal monitoring procedure performed during the second and third trimesters to check how well the baby is doing in the womb. The test measures the fetal heart rate and monitors how it changes when the baby moves, without any invasive procedures or labor induction.

During an NST, two sensors are placed on the mother's abdomen. One sensor tracks the fetal heart rate using ultrasound technology, while the other detects uterine contractions and fetal movement. The mother sits comfortably in a reclined chair for about 20 to 30 minutes while the monitor records data. She may be asked to press a button when she feels the baby move, which helps correlate movements with heart rate changes.

Doctors order an NST when they need reassurance about fetal health, particularly in higher-risk pregnancies. Common reasons include monitoring pregnancies with gestational diabetes, high blood pressure, or previous pregnancy complications, as well as when a mother reports decreased fetal movement or when the pregnancy extends past the due date. A healthy response shows the fetal heart rate increases with movement, which is a sign of good fetal oxygenation and nervous system function.

The test is called "non-stress" because it does not stress the fetus or trigger labor. Results are typically available immediately, with a "reactive" result (normal) indicating the baby is well, or "non-reactive" prompting further evaluation. Prenatal care centers in Kuala Lumpur routinely perform NSTs as part of standard late-pregnancy monitoring protocols.