A non-stress test (NST) is a way to externally monitor a baby's fetal heart rate (FHR). This test can be done as early as the 27th week of pregnancy. It measures the unborn baby's FHR as it accelerates with normal development.
When having this test done, you'll sit on a slightly reclined doctor's chair with your knees and back somewhat elevated, and a cushion under your right hip (to move your uterus to your left side).
The same type of monitors used during a external fetal monitoring (EFT) are employed during this test (sensors placed on your abdomen). These monitors will track your baby's FHR and any contractions you might be having. If the test registers no activity after 30 to 40 minutes, you will be given something sweet and or cold to drink or a snack, to stimulate your baby. A nurse may also gently place her hands on your abdomen to move your baby.