Fetal Non-Stress Test (NST)

During some pregnancies, special testing may be recommended. Usually, these tests are done when there is an increased risk of pregnancy complications. One test that may be recommended for some women is a fetal non-stress test.

What is a Fetal Non-Stress Test (NST)?

A non-stress test (NST) is a type of test that may be done during pregnancy. It is used to measure the heart rate of the fetus in response to fetal movement. It checks for “accelerations” in the heart rate over a certain amount of time. The term “non-stress” means that the test does not place any stress on the fetus and is safe for both mother and baby.

Why Non-Stress Tests Are Performed

A fetal non-stress test is often performed when the pregnancy is high risk or the mother goes past her due date. Some conditions that may prompt your doctor to recommend an NST include:

  • Pre-existing or gestational diabetes
  • Multiples pregnancy
  • Heart disease
  • Clotting disorders
  • Thyroid disorders
  • High blood pressure

An OB/GYN may also recommend a fetal non-stress test if there are signs that there is too much or too little amniotic fluid or if the baby is not moving as much as usual.

How an NST is Performed

An NST can be done in the Raliegh OB/GYN office. During the test, you will recline or lie down. A belt with a fetal heart rate sensor is placed around your abdomen. The fetal heart rate is recorded by a machine. The test usually takes at least 20 minutes. 

According to the American College of Obstetricians of Gynecologists (ACOG), if two or more fetal heart rate accelerations occur within a 20 minute period, the results are considered reactive. This means that it does not appear that there are any problems. 

A nonreactive result means there are not enough accelerations within a 40-minute period. If this occurs, the test may need to continue for 40 more minutes. However, your doctor can discuss the next steps with you if you have a nonreactive result after 40 minutes.

Contact Raleigh OB/GYN Centre

The physicians, nurses, and medical staff at Raleigh OB/GYN offer a comprehensive list of gynecological and obstetric services to the women of the Raleigh, NC area. If you have questions about special tests like NST, call our office at (919) 876-8225 to make an appointment.