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

A mom-to-be with a high-risk pregnancy cherishes every bit of positive feedback she can get. A non-stress test can tell you more about how your baby is doing in the final weeks of pregnancy.

Most expectant parents want reassurance that they will deliver a healthy baby. Understandably, a woman who is told her pregnancy is high risk is likely to worry more than someone without pregnancy problems. Even healthy women are sometimes given special tests as a precaution to monitor their baby’s health late in the pregnancy.

“The non-stress test is a special test we like to perform in some moms who are considered to have a high-risk pregnancy or when she develops problems during her pregnancy,” says Ob/Gyn Edward Chien, MD, MBA. “We often recommend these special tests starting at 32 or 34 weeks in moms who have an ongoing condition, although sometimes we’ll begin monitoring the baby’s 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 baby, such as appearing too small, being diagnosed with a birth defect or being less active than normal.
• Situations where the mom previously lost a baby in the second half or later in pregnancy.

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

• A woman is age 35 or older.
• The pregnancy lasts longer than 41 weeks and they want to check on the baby’s health.

What happens during a non-stress test?

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

The test looks at the baby’s heart rate along with the fluctuations in the heart rate. We also evaluate the number of movements the baby makes during the monitoring period. If the baby is sleeping or inactive during the test, we may ask the mother to drink cold water or juice to get them moving.

The test outcome is either reactive or nonreactive. A reactive result means the baby’s 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. We are also looking for a decline in the baby’s heart rate. If it is nonreactive or declines are noted, your doctor may want you to take additional tests to make sure your baby is healthy.