When it’s done: After 28 weeks
Your doctor may order this test if you don’t feel your baby kick often or have a high-risk pregnancy. For this test, a special belt is placed around your abdomen to measure the baby’s heart rate in response to its own movements. An NST is often performed biweekly in high-risk pregnancies.
Sometimes an NST is done along with an ultrasound to assess the health of an unborn baby. These tests together are called a biophysical profile or BPP and can determine if the baby should be delivered early. It can take up to 20 minutes to perform a BPP.