NCC EFM STUDY GUIDE
Causes of uteroplacental perfusion decrease: ~ • HTN
• Pregnancy
• DM
• Hypotension
• Excessive uterine contractions (hypertonus)
• Decreased surface area, edema, degenerative calcifications, infarcts,
infection
FHR reflects fetal oxygenation from which extrinsic factors: ~ • Maternal
oxygenation
• Uterine blood flow
• Placental change
• Umbilical blood flow
FHR reflects oxygenation from which intrinsic factors: ~ • Fetal circulation
• Oxygenation of tissues
• FHR regulation
Fetal shunts: ~ • Ductus venosus- liver
• PFO- Right to left atria
• Ductus arteriosis- pulmonary a. to aorta
Oxygen depletion cascade: ~ • Aerobic metabolism
• Hypoxemia
• Tissue hypoxia
• Anaerobic metabolism
• Lactic acid build up
• Metabolic acidosis
Sympathetic innervation: ~ • Releases Eip/norepi
• Increases FHR
Parasympathetic/Vagal innervation: ~ • Releases ach
• Decreases FHR and transmits variability
Early decel: ~ • Fetal head compression
• ->vasovagal response
Variable decel: ~ • Cord compression
• ->increase BP/HTN
• ->activation of baroreceptor
• ->decrease FHR, BP, and CO
, Late decel: ~ • Inadequate uteroplacental blood flow->decreased maternal
fetal O2 transfer
• ->activation of chemoreceptors to respond due to increased PCO2,
decreased PO2, and decreased pH
• ->Fetal bradycardia and hypertension
Category I: ~ • Normal fetal acid base status
• All the following are required:
• Moderate variability
• Baseline rate 110-160
• Late or variable decels are absent
• Early decels present or absent
• Accels present or absent
Category II: ~ • Indeterminate compensatory response
• Not category I or II
Category III: ~ • Abnormal fetal acid-base status
• Either required
• Absent variability with:
o Recurrent late decels, or
o Recurrent variable decels, or
o Bradycardia
• Sinusoidal pattern
In-Utero resuscitation: ~ • Change maternal position
• Decrease uterine activity
• IV fluid bolus
• Correct maternal hypotension
• Oxygen administration
• Amnioinfusion
• Alteration in 2nd stage maternal pushing efforts
• If prolapsed cord, then elevate fetal presenting part while moving toward
operative birth
Baseline FHR: ~ • Approximate mean FHR excluding accelerations and
decelerations or periods of marked variability (>25 bpm)
• Minimum of 2 minutes of identifiable BL segments in any 10 min window
• May need to refer to previous 10 min window
Baseline variability: ~ • Irregular fluctuation in baseline FHR in both
amplitude and frequency
• Absent- Undetectable
• Minimal- 0-5
• Moderate- 6-25
Causes of uteroplacental perfusion decrease: ~ • HTN
• Pregnancy
• DM
• Hypotension
• Excessive uterine contractions (hypertonus)
• Decreased surface area, edema, degenerative calcifications, infarcts,
infection
FHR reflects fetal oxygenation from which extrinsic factors: ~ • Maternal
oxygenation
• Uterine blood flow
• Placental change
• Umbilical blood flow
FHR reflects oxygenation from which intrinsic factors: ~ • Fetal circulation
• Oxygenation of tissues
• FHR regulation
Fetal shunts: ~ • Ductus venosus- liver
• PFO- Right to left atria
• Ductus arteriosis- pulmonary a. to aorta
Oxygen depletion cascade: ~ • Aerobic metabolism
• Hypoxemia
• Tissue hypoxia
• Anaerobic metabolism
• Lactic acid build up
• Metabolic acidosis
Sympathetic innervation: ~ • Releases Eip/norepi
• Increases FHR
Parasympathetic/Vagal innervation: ~ • Releases ach
• Decreases FHR and transmits variability
Early decel: ~ • Fetal head compression
• ->vasovagal response
Variable decel: ~ • Cord compression
• ->increase BP/HTN
• ->activation of baroreceptor
• ->decrease FHR, BP, and CO
, Late decel: ~ • Inadequate uteroplacental blood flow->decreased maternal
fetal O2 transfer
• ->activation of chemoreceptors to respond due to increased PCO2,
decreased PO2, and decreased pH
• ->Fetal bradycardia and hypertension
Category I: ~ • Normal fetal acid base status
• All the following are required:
• Moderate variability
• Baseline rate 110-160
• Late or variable decels are absent
• Early decels present or absent
• Accels present or absent
Category II: ~ • Indeterminate compensatory response
• Not category I or II
Category III: ~ • Abnormal fetal acid-base status
• Either required
• Absent variability with:
o Recurrent late decels, or
o Recurrent variable decels, or
o Bradycardia
• Sinusoidal pattern
In-Utero resuscitation: ~ • Change maternal position
• Decrease uterine activity
• IV fluid bolus
• Correct maternal hypotension
• Oxygen administration
• Amnioinfusion
• Alteration in 2nd stage maternal pushing efforts
• If prolapsed cord, then elevate fetal presenting part while moving toward
operative birth
Baseline FHR: ~ • Approximate mean FHR excluding accelerations and
decelerations or periods of marked variability (>25 bpm)
• Minimum of 2 minutes of identifiable BL segments in any 10 min window
• May need to refer to previous 10 min window
Baseline variability: ~ • Irregular fluctuation in baseline FHR in both
amplitude and frequency
• Absent- Undetectable
• Minimal- 0-5
• Moderate- 6-25
