Nonstress test can be a very reliable noninvasive test for fetal well-being. It is measuring the fetal heart rate in response to fetal activity on a fetal monitor.
In a nonstress test, the woman is placed on an electronic fetal monitor and when the heart rate is noted. The woman is given a control to push when she feels the baby move. The control places a mark on the readout. Sometimes, a transducer is used to make a buzzing sound over the baby’s head. When this is done, the test is called a vibroacoustic stimulation test (VST). An increase in the fetal heart rate indicates fetal well-being. If the result is negative, additional testing, such as an oxytocin challenge test, is usually required.
Nonstress test results can be affected by low blood sugar, so you should eat before taking the test. The results can also be affected by illness of the fetus.