What is a nonstress test?
A nonstress test uses electronic monitoring to check the
health of an unborn baby. An external fetal monitor is
attached to the mother and records the baby's heart rate.
When a healthy baby moves, the baby's heart rate goes up.
When is it used?
You may have this test if:
- You have a high-risk condition, such as high blood
pressure or a baby that is not growing properly.
- You had problems in a previous pregnancy, such as a
baby who died at birth.
- You have noticed that your baby is moving less.
- You are past your due date.
- You have a disease, such as diabetes.
The test is most reliable when it is done:
- in the last 6 to 8 weeks of pregnancy
- at the time of day when the baby is most active (1 to 2
hours after you eat a meal).
Several nonstress tests may need to be done to show the
baby's well-being over time.
How do I prepare for a nonstress test?
- If you smoke, do not smoke for at least 4 hours before the
test.
- Eat a full breakfast or lunch before the test.
What happens during the procedure?
An external electronic fetal monitor is strapped to your
abdomen. You will have a button to push when you feel the
baby move. The monitor will record the baby's heart rate.
The results of the test are classified as follows:
- Reactive: The baby moves two or more times in 20 minutes.
During at least two of these movements, the heart rate
increases by 15 beats a minute and stays increased for at
least 15 seconds. Reactive results of this test are a
sign that the baby is healthy.
- Nonreactive: Either the baby doesn't move or the heart
rate doesn't rise enough during movements.
Often a test is nonreactive because the baby is not moving
enough to get good readings. Then the test must be done
again when the baby is more active. Sometimes drinking a
glass of cranberry or orange juice will help the baby become
more active. Or a device that makes a noise like a buzzer
may be placed against your abdomen to awaken the baby.
If another test is again nonreactive, an ultrasound test
called a biophysical profile may be done. If the well-being
of the baby is still unclear, a contraction stress test may
be done.
What happens after the procedure?
You may need to repeat the test 3 to 7 days later. You may
need to have the test several times. In some cases your
health care provider may recommend an early delivery.
What are the benefits of this test?
- If the test result is abnormal, it helps identify a baby
that may have problems during labor. As a result of the
test, your provider may do more tests and may consider
delivering the baby before labor starts.
- If the test result is normal, it can reassure the mother
that the baby will probably do well during labor unless
new problems develop.
What are the risks of this test?
The test does not pose any risks to you or the baby.


Disclaimer: This content is reviewed periodically and is subject to
change as new health information becomes available. The
information provided is intended to be informative and educational and is not a
replacement for professional medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
HIA File WOM5305F.HTM Release 9.0/2006. Copyright © 2006 McKesson Corporation and/or one of its subdiaries. All Rights Reserved.
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