Nonstress Test Test
A nonstress test (NST) checks your baby's heart rate during movement or contractions to see if they are getting enough oxygen.
What this test measures
The test measures the heart rate of your developing baby as the baby moves or when you have contractions in your uterus.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Frequently asked questions
What is a nonstress test?
A nonstress test (NST) is a safe and painless test given during pregnancy to check your baby's heart rate.
When is a nonstress test usually done?
The test is usually done in the third trimester, most often after 28 weeks.
What does a reactive result mean?
A reactive or reassuring result means your baby's heart rate increased two or more times during the testing period.
What does a nonreactive result mean?
A nonreactive result means your baby's heartbeat didn't increase when moving or the baby wasn't moving much.
Does a nonreactive result always mean a health problem?
No. A nonreactive result doesn't always mean your baby has a health problem. Your baby may have been asleep or not easily awoken.
Related lab tests
Sources
- MedlinePlus: Nonstress Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.