Electronic Fetal Monitoring

• Five essential components of EFM

  1. Baseline FHR
  2. Variability
  3. Accelerations
  4. Decelerations
  5. Changes in FHR over time
• Internal Fetal Monitoring

  • Invasive: membranes must be ruptured, cervix sufficiently dilated and presenting part low
  • Spiral electrode for FHR
  • IUPC for uterine contractions
• Peak intensity

  With IUPC: 50-75 mmHg, up to 110 mmHg with pushing
• Resting tone

  Want 5-15 mmHg, up to 20 mmHg
• Frequency

  3-5 contractions averaged over 10 minutes

  More than 5= tachysystole
• Resting time

  At least 30 seconds between contractions
• Duration

  45-60 seconds in active phase

  60-120 seconds in transitional phase and pushing (stage 2)
• Fetal Tachycardia:

  • FHR more than 160 bpm lasting longer than 10 minutes
  • Causes: fetal hypoxia, *maternal fever*/dehydration, maternal drugs, infection, maternal hyperthyroidism, fetal anemia, and fetal heart failure
  • NON-reassuring sign when associated with late decels, severe variable decels or absence of variability
• Fetal Bradycardia:

  • FHR less than 110 bpm lasting longer than 10 minutes
  • Causes: fetal hypoxia, maternal supine position/hypotension, *prolonged umbilical cord compression*/cord prolapse, fetal congenital heart block, uterine tachysystole, abruptio placentae, uterine rupture, vagal stimulation (rapid fetal descent), maternal drugs.
  • NON-reassuring sign when associated with loss of variability or late decelerations
• Baseline variability:

  • Absent: undetectable
  • Minimal: detectable but equal or less than 5 bpm
  • Average/moderate: 6-25 bpm
  • Marked: more than 25 bpm
  • Presence of moderate variability is strongly associated with adequate cerebral oxygenation
• Absent variability:

  • Amplitude range undetectable
  • Causes: *hypoxia*, acidosis, reaction to drugs, fetal prematurity, congenital anomalies, and preexisting neurologic insult
  • NON-reassuring
• Minimal variability:

  • Amplitude is detectable but less or equal to 5 bpm
  • Consider the three S's: SLEEP, SEDATION, SICK (Hypoxic)
  • NON-reassuring
• Average/Moderate variability

  • Amplitude: 6-25 bpm
  • Strongly associated with adequate cerebral oxygenation
  • REASSURING!
• Marked variability

  • Amplitude: more than 25 bpm
  • Causes: mild hypoxia, fetal activity and alterations in placental blood flow
  • Need for continued frequent assessment
• Sinusoidal Patterns

  • Smooth, wave-like pattern
  • Rate of 3-5 per minute for more than 10 minutes
  • Occurs with: fetal asphyxia/hypoxia, fetal infection, severe fetal anemia (Rh isoimmunization & fetal bleeds)
  • Psuedosinusoidal: medication effection (narcotics)
  • Category III, NON-reassuring
• Accelerations:

  • Temporary increase in FHR above the baseline
  • Visual increase in FHR above BL of 15 bpm for 15 seconds
  • Normally caused by fetal movement or in response to uterine contractions
  • Caused by sympathetic response to fetal movement
  • Generally reassuring
• Early decelerations:

  • Caused by head compression resulting in vagal reflex
  • Inversely mirror contractions in beginning, end and nadir/peak
• Late decelerations:

  • Caused by uteroplacental insufficiency
  • FHR returns to baseline after contractions ends
• Late decelerations:

  • Related to presence of fetal hypoxemia
  • Nursing actions: reposition, hydrate, oxygen, discontinue oxytocin, and notify provider
  • Always NON-reassuring!
• Variable decelerations:

  • Caused by umbilical cord compression
  • Usually a V shape
  • Non-reassuring if repetitive
  • More common following ROM
  • Nursing actions: reposition*, hydrate, oxygen, notify provider and amnioinfusion*
• Prolonged Deceleration:

  • Often caused by prolonged cord compression
  • Never reassuring
  • Abrupt decrease in FHR of at least 15 bpm below baseline, lasting 2-10 minutes
• V: Variable decelerations

  E: Early decelerations

  A: Accelerations

  L: Late decelerations

  C: Cord compression/prolapse

  H: Head compression

  O: Okay

  P: Placental insufficiency
• Nursing interventions for Non-reassuring patterns:

  • Maternal reposition
  • Maternal VS to identify hypotension, HTN, fever
  • Hydrate
  • IV fluids
  • Oxygen via facemask at 8-10 L/minute
  • Stop oxytocin
• Category I (Normal):

  • Baseline rate: 110-160 bpm
  • Moderate variability (6-25)
  • NO late or variable decels
  • Early decels (absent or present)
  • Accelerations (absent or present)
• Category III (WORST)

  • Absent variability with recurrent late decels, recurrent variable decels, or bradycardia OR sinusoidal pattern