Prenatal non-stress test (NST), also known as fetal heart rate monitoring, is a simple and painless test carried out during pregnancy for assessing the overall condition of the fetus. This test is usually performed during the 26 to 28 weeks of pregnancy and is non-invasive in nature.
The main procedure involved in the test is the monitoring of the heart rate of the fetus. The movements and the heart rate of the fetus are measured for about 20 to 30 minutes. Prenatal non-stress is carried out across all of the affordable health clinics in the country.
The prenatal non-stress test is usually performed when the fetus is prone to any health risk factors. If the fetus is not showing any of frequent movements, it indicates a problem and the non-stress test is performed for evaluating the health condition.
The test can provide accurate results regarding the health of the fetus and other conditions such as insufficient reception of oxygen due to any problems in the placental or umbilical cord. However, the test is performed only after 18 weeks in the pregnancy period, as the fetus will not be developed well to respond to the tests before that.
The importance of carrying out the non-stress test is highlighted in the fact that it will help prevent any complications that may arise during the final stages of pregnancy. The main aim of performing an NST is to evaluate the heart rate of the fetus in its movements. A healthy fetus will positively respond to any signs of movement with an increase in the heart rate, which will lower while the baby is resting.
The non-stress test is based on the concept that the fetus will show movements and normal heart rate if it receives adequate oxygen. Low oxygen levels can cause the fetus to not respond normally. A reactive test result is obtained if the heart rate of the fetus is recorded at least 15 beats per minute for a period of 15 seconds. This is done twice in a 20-minute span to confirm that the fetus is normal.
A non-reactive test result is obtained if the fetal heart rate does not change according to its movements. However, it does not mean that the fetus is having a problem. The test may yield only a little information and is repeated after an hour for getting results that are more accurate.