What to Expect During a Non-Stress Test When You’re Pregnant

If you're going through a high-risk pregnancy, you cherish every bit of positive feedback you can get. A non-stress test can tell you more about how your fetus is doing in the final weeks of pregnancy.

Most expectant parents want reassurance that they will deliver a healthy baby. And if you're pregnancy is high risk, you may worry even more. Even healthy women are sometimes given special tests as a precaution to monitor their fetus' health late in the pregnancy.

“The non-stress test is a special test we like to perform if you are considered to have a high-risk pregnancy, or if you develop problems during your pregnancy,” says Ob/Gyn Edward Chien, MD, MBA. “We often recommend these special tests starting at 32 or 34 weeks if you have an ongoing condition, although sometimes we’ll begin monitoring the fetus' movements as early as 28 weeks.”

Who might need a non-stress test?

Certain conditions warrant non-stress testing and determine how frequently the tests are done. These health conditions can include:

• Diabetes, chronic hypertension and other pre-existing health conditions.
• Problems that arise during pregnancy, such as new onset high blood pressure or gestational hypertension.
• Issues with the fetus, such as appearing too small, being diagnosed with a fetal abnormality or being less active than normal.
• Past miscarriage(s) in your second trimester or later.

Other instances when your doctor might order a non-stress test are:

• If you're over 35.
• If your pregnancy lasts longer than 41 weeks and they want to check on the fetus' health.

What happens during a non-stress test?

Non-stress tests – these do not put any stress on the fetus — are used to monitor fetal movement. The noninvasive test can take anywhere from 20 to 90 minutes, depending on how active the fetus is. Usually, the test is performed in your doctor’s office or at the hospital.

The test looks at fetal heart rate and fluctuations. Providers also evaluate the number of movements the fetus makes during the monitoring period. If the fetus is inactive during the test, your provider may ask you to drink cold water or juice.

The test outcome is either reactive or nonreactive. A reactive result means the fetus' heart beats faster than their resting rate at least twice during the test. This is considered reassuring. A nonreactive result means their heart rate doesn’t accelerate. Your provider's also looking for a decline in the fetal heart rate. If the fetus is nonreactive or declines are noted, your doctor may want you to perform additional tests to make sure everything'd okay.