Fetal Heart Monitoring Flashcards
What is the basal fetal heart rate and why?
150-160bpm
-the sympathetic nervous system develops first and controls the HR
What occurs when the parasympathetic nervous system develops?
Variability in the HR.
-a flat rate is often indicative of a nervous system developmental problem
What is the definition of normal FHR, tachycardia and bradycardia?
Normal: 110-160bpm
Tach: greater than 160
Brady: less than 110
Top two causes of fetal tachycardia.
Maternal fever
Infection
Main cause of fetal bradycardia.
Hypoxemia
What is variability?
Changes in fetal HR over time. Occurs once the parasympathetic nervous system develops. The more variability the better.
What are accelerations and decelerations?
Accel: increase in FHR in response to uterine contraction
Decel: decrease in FHR in response to uterine contraction (early, late, variable, mixed)
What causes early decelerations?
Usually fetal head compression initiating a vagal response. Not associated with fetal distress.
Curve overlaps (mirrors) the uterine contraction
What causes late decelerations?
Associated with uteroplacental insuffiency.
Curve shifted to the right of uterine contraction
How is the severity of late deceleration categorized?
Mild: less than 15bpm decrease in FHR
Moderate: 15-45bpm decrease
Severe: greater than 45bpm decrease
Cause of variable decelerations.
Umbilical cord compression
First and most important step for managing variable decelerations.
Stop Pitocin
What is meconium?
Passage of fetal stool in the amniotic fluid.
Tx for meconium?
Amnioinfusion
At what fetal pH is the fetus distressed?
Less than 7.25
