Non-Stress Test (NST)
Monitoring test that tracks baby's heart rate and movements to assess well-being in late pregnancy.
📅 When Performed
Third trimester, usually after 28 weeks
⏱️ Results Timeline
Immediate - results reviewed right away
Overview
A non-stress test (NST) monitors your baby's heart rate and movement to ensure your baby is getting enough oxygen and responding normally. It's called "non-stress" because nothing is done to stress or challenge the baby - you simply rest while being monitored.
The test looks for accelerations in baby's heart rate when baby moves. A healthy baby's heart rate speeds up with movement. If the heart rate doesn't accelerate appropriately, it may indicate the baby needs further evaluation.
NSTs are often performed weekly or twice weekly in the third trimester for women with certain pregnancy complications or when the pregnancy goes past the due date.
🎯 Purpose of Test
- •Assess baby's well-being in late pregnancy
- •Monitor baby's heart rate response to movement
- •Check that baby is getting adequate oxygen
- •Surveillance in high-risk pregnancies
- •Monitor post-dates pregnancies (after 40-41 weeks)
- •Evaluate decreased fetal movement
🔬 How It's Performed
- 1.Two sensors placed on your belly with elastic belts
- 2.One sensor monitors baby's heart rate
- 3.Second sensor detects contractions
- 4.You lie semi-reclined or on left side
- 5.Monitoring typically lasts 20-30 minutes
- 6.Push button when you feel baby move
- 7.May be given juice or snack to encourage movement
- 8.Printout shows baby's heart rate pattern
👀 What to Expect
- →Rest comfortably in reclining chair or bed
- →Monitoring is completely painless
- →May hear baby's heartbeat
- →Baby may or may not be active during test
- →If baby is sleeping, test may take longer
- →External vibration may be used to wake baby
- →Usually takes 20-40 minutes
- →May need extended monitoring if baby not active
✓ Normal Results
Reactive NST: Two or more heart rate accelerations of 15 bpm lasting 15 seconds within 20 minutes. Baby is doing well.
⚠️ Abnormal Results
- •Non-reactive NST: Insufficient heart rate accelerations
- •Doesn't always mean problem - baby may be sleeping
- •Extended monitoring or biophysical profile ordered
- •May need additional testing same day
- •Rarely indicates need for immediate delivery
- •Often followed up with ultrasound
- •May indicate need for closer monitoring
⚠️ Risks & Considerations
- •No risks to mother or baby
- •Completely non-invasive
- •Time-consuming appointment
- •Anxiety if results non-reactive
- •False positive results possible
📝 How to Prepare
- →Eat a meal or snack before test (helps baby be active)
- →Drink juice before arriving
- →Bring something to do (book, phone, headphones)
- →Empty bladder before test
- →Wear comfortable clothing
- →Plan for 45-60 minutes at office
- →Bring partner or support person if desired