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Snapshot
  • A 35-year-old woman at 42 weeks of gestation presents for an induction of labor due to postterm pregnancy. She reports positive fetal movement, and denies vaginal bleeding. After amniotomy is performed, a change in fetal heart monitor is noted. Maternal repositioning is performed. (Variable decelerations)
Biophysical Profile (BPP)
  • Five measurements of fetal well being, each rated on scale of 1-2
    • measure
      • fetal breathing
      • gross body movements
      • fetal tone
        • extremity extension and flexion
      • amniotic fluid volume
      • nonstress test (NST)
  • Scoring
    • 8-10 is reassuring
    • 6 is equivocal
      • delivery if > 36 weeks
      • repeat BPP in 24 hours if < 36 weeks
    • ≤ 4 is abnormal
      • requires immediate intervention 
Fetal Heart Rate (FHR)
  • Normal FHR 120-160/min
  • Tachycardia is FHR > 160/min
    • causes include
      • maternal fever
      • fetal hypoxia
      • prematurity
      • anemia (maternal or fetal)
      • chorioamnionitis
      • hyperthyroidism
  • Bradycardia is FHR < 110/min for > 10 minutes
    • causes include
      • congenital heart block
      • maternal β-blockers
  • FHR variability
    • reliable indicator of fetal well being
    • causes of decreased variability include
      • fetal hypoxia
      • congenital heart anomalies
Electronic Fetal Heart Rate Monitoring (EFM) Tracing Interpretation
  • Accelerations
    • FHR at least 15/min above baseline for 15 seconds in a 20 minute period
      • considered a reactive NST (needs the presence of at least 2 accelerations)  
    • suggests fetal well being
  • Early decelerations
    • FHR (not below 100/min) that coincide with uterine contraction
    • results from pressure on fetus head resulting in vagus nerve stimulation and reflex bradycardia
    • physiologic and not harmful to fetus  

  • Variable decelerations
    • may not coincide with uterine contractions
    • rapid in FHR (often < 100/min) with variable recovery
    • reflex mechanism due to umbilical cord compression
      • rupture of membrane can lead to umbilical artery compression
    • correct by shifting maternal position or amnioinfusion if membranes ruptured
      • considered first-line
      • if maternal repositioning does not improve FHR tracing, amnioinfusion can be considered

  • Late decelerations
    • begins after uterine contraction has started
    • associated with uteroplacental insufficiency and viewed as potentially dangerous 
    • causes include
      • placental abruption
      • maternal diabetes
      • maternal anemia
      • maternal sepsis
      • postterm pregnancy
      • hyperstimulated uterus
    • repetitive late develerations require intervention

  • Sinusoidal tracing
    • sine-wave like pattern
    • associated with increased morbidity and mortality
    • indicative of severe fetal anemia
      • e.g., severe hypoxia and Rh disease


 

 

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