Stress Test vs. Non-Stress Test

Stress Test

A patient is given an injection of a drug to mimic mild labor. In the test, the doctors monitor the fetal heart rate in response to induced mild contractions of the uterus.

How do they monitor the baby's heart rate?

The mother is hooked up to an external electronic fetal monitor. The monitor typically records the baby's heart rate for 20 minutes.

When is the test performed?

It is typically performed in the later stages of the pregnancy most frequently between 38 and 42 weeks. It can be done as early as the beginning of the third trimester, but is mostly common test when a mother has gone past her expected due date. It also is performed as a precautionary measure if a mother had experienced any problems in previous pregnancies such as diabetes or intrauterine growth retardation.

If you're overdue, you may also be scheduled for a non-stress test, and may need to have it repeated every day or every few days to confirm the baby is well.

How the test is done:

This test is usually done in a doctor's office. The pregnant mother will either sit in a chair or lie on a table. Fetal monitoring equipment will be placed to her belly. The equipment will record the baby's heart rate and compare it to activity in the uterus.

Non-Stress Test

It is similar to the stress test, but the labor-mimicking drug is not administered. In the non-stress test, the mother is hooked up to an external electronic fetal monitor, which typically records the baby’s heart rate for 20 minutes.

Neither of these tests pose any risk to the mother or baby.