NST
Also written as: NST — Non-stress test
Non-stress test; a prenatal monitoring procedure that records fetal heart rate patterns in response to fetal movement.
Full Definition
The non-stress test (NST) is a non-invasive prenatal screening tool used to evaluate fetal well-being by monitoring fetal heart rate patterns and their relationship to fetal movement. The test involves placing external monitors on the maternal abdomen to record fetal heart rate and uterine activity over a 20-40 minute period. A 'reactive' NST shows appropriate fetal heart rate accelerations with movement, indicating adequate fetal oxygenation. Non-reactive results may require additional testing such as biophysical profiles or contraction stress tests. NSTs are commonly performed in high-risk pregnancies, post-term pregnancies, or when decreased fetal movement is reported.
Usage
Usage note: Distinguish from CST (contraction stress test) which involves induced contractions.
In Context
- "The NST was reactive with two accelerations lasting 15 seconds above baseline." — Antepartum testing report
- "Weekly NSTs are scheduled for patients with gestational diabetes after 32 weeks." — High-risk pregnancy protocol