nonstress_test
Reviewed
Also called: fetal nonstress test, categoryDetailsList: [
A safe, painless test in the third trimester (usually after 28 weeks) that measures the baby's heart rate in response to movement or contractions. It helps check the baby's health before birth.
Specimen: not applicable
Why this test may be ordered
- Baby seems to be moving less than usual
- Pregnancy is overdue (42 weeks or beyond)
- High-risk pregnancy due to chronic conditions (e.g., high blood pressure, diabetes, heart disease, clotting disorder)
- Complications in a previous pregnancy
- Rh incompatibility (mother Rh-negative, baby Rh-positive) that may cause immune attack on baby's red blood cells
Preparation and collection
No special preparation; you may be asked to empty your bladder before the test.
You lie on a reclining chair or exam table. Gel is applied to your abdomen, and two belt-like devices are attached: one measures the baby's heartbeat, the other records contractions. You may press a button when you feel movement. The test lasts about 20–30 minutes. If the baby is asleep, a small buzzer or noisemaker may be used to wake them.
There is no risk to you or your baby from having a nonstress test.
Understanding results
Results are given as reactive (reassuring) or nonreactive. A nonreactive result does not always mean a health problem; the baby may have been asleep or certain medicines may affect the result.
- Reactive (Reassuring): The baby's heart rate increased two or more times during the testing period. Limitation: None specified in the source. Next step: Routine follow-up with your provider.
- Nonreactive: The baby's heartbeat did not increase when moving, or the baby was not moving much. Limitation: May be due to the baby being asleep or certain medicines taken during pregnancy. Does not always mean a health problem. Next step: Your provider will likely take more tests to determine if there is cause for concern. If the baby is found to be at risk, treatment, monitoring, or induction of labor may be needed.
- A nonreactive result does not always mean the baby has a health problem; the baby may have been asleep or certain medicines may affect the result.
- Additional testing (e.g., biophysical profile, contraction stress test) may be needed to clarify results.
What to do next
If you have questions about your results, talk to your provider.
- What does my result mean for my baby's health?
- If my result was nonreactive, what additional tests might be needed?
- How often should I have this test during my pregnancy?