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Mothers and babies who need special medical care and extra attention may need a nonstress test (NST). An NST is a simple, painless procedure. We will be monitoring your baby’s heartbeat, which is a way of evaluating your unborn baby. We will listen to and record the baby’s heartbeat while the baby is resting and while the baby is moving. It usually takes 20 to 40 minutes to complete an NST.
Frequently Asked Questions
Why is an NST performed?
Some common reasons for an NST are:
Who will do the test?
A nurse who specializes in fetal testing will perform the NST.
When will the NST be done?
NSTs are usually performed once or twice a week. You will be given an appointment for your next NST. We will try to schedule your test for the same day as your doctor’s visit.
What can I expect during the NST?
- We would like you to eat before the test because some babies move more after their moms have eaten.
- You will be more comfortable if you empty your bladder before the NST. We will ask you to lie on your left side for the test. The two fetal monitor pieces will be placed on your abdomen and held in place by elastic belts. One piece records the baby’s heartbeat and movement. The other device records any contractions of your uterus.
- We will be looking at the baby’s movement and heart rate. Just as your heart beats faster when you run up a flight of stairs, your baby’s heart should beat faster when kicking and moving.
- The NST is reactive if the heart beats faster when the baby moves. This must happen at least two times in 20 minutes. If your baby is quiet and not moving, the nurse may give you juice or water to drink.
- The NST is nonreactive if the heart does not beat faster when the baby moves or if the baby is quiet and not moving. This does not mean that something is wrong! It simply means the NST has not given us enough information. Additional tests may be needed, such as a biophysical profile or contraction stress test.
Where will the test be done?
The test will be performed in the Fetal Assessment Center, which is located on the second floor of the Nelson/Harvey Building, room 278. Please bring your Johns Hopkins Hospital plate and insurance information for each scheduled test.
Once the test is completed, it is reviewed by a maternal-fetal medicine specialist, and recommendations for ongoing testing/intervention are made.