NM704 EXAM 2 ACTUAL QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
Define Baseline FHR
Mean FHR rounded to increments of 5 bpm during a 10 minute window; (excluding
accelerations or decelerations, or periods of marked FHR variability)
Define fetal bradycardia
FHR <60
Define fetal tachycardia
FHR >160
Define baseline FHR variability
Determined in a 10 minute window excluding accelerations and decelerations;
fluctuations in BL FHR that are irregular in amplitude and frequency; no distinction
between short term and long term, visually determined as a unit;
Quantitated as the amplitude between peak-to-trough
Absent: undetectable
Minimal: detectable but equal to or less than 5 bpm
Moderate: 6-25 bpm
Marked: greater than 25 bpm
Define Acceleration
Abrupt increase in FHR above baseline;
After 32 weeks: greater than or equal to 15 bpm above baseline lasting at least 15
seconds and less than 2 minutes from onset to return to baseline
,Before 32 weeks: greater than or equal to 10 bpm above baseline lasting at least 10
seconds from onset to baseline
Define Early Deceleration
Symmetrical gradual decrease and return of the FHR associated with a uterine
contractions; decrease is calculated from onset to the nadir of the deceleration
Define Late Deceleration
Symmetrical gradual decrease and return of FHR associated with a uterine contraction;
delayed in timing with nadir occurring after the nadir of the contraction
Define Variable Deceleration
Abrupt decrease in FHR
Onset of the decel to the beginning of the FHR nadir of less than 30 seconds
Decrease is 15 bpm or greater and duration lasting less than 2 minutes
Associated with contraction, onset and depth, duration is commonly varied with
successive uterine contraction
Define prolonged deceleration
Decrease in FHR of 15 bpm or more, duration 2 minutes or longer but less than 10
minutes
Understand the following physiologic mechanisms responsible for normal fetal
heart rate patterns.
Sympathetic input
Sympathetic nerve fibers innervate the myocardium responding to catecholamine
stimulation by increasing the FHR
Parasympathetic input
, Matures during second trimester, mediated by the vagus nerve, becomes dominate over
sympathetic stimulation during seconds trimester leading to gradual decrease in FHR
Chemoreceptors
Sensitive to changes in the oxygen and CO2 content within the blood; increased CO2
causes chemoreceptors to signal the medulla oblongata which then signals the vagus
nerve which then slows the FHR
Baroreceptors
Detects changes in pressure; any stressful situation in the fetus then evokes the
baroreceptor reflex, which elicits selective peripheral vasoconstriction and hypertension
with a resulting bradycardia
Causes of fetal bradycardia
Bradycardia : two types (aspysxia and non-asphyxial
Asphyxia causes; prolapse cord, placental abruption, uterine prolapse, vasa-p nything
<60 bpm is an emergency
Non-asphyxial causes: fetal heart block; maternal hypothermia; mild bradycardia
(idiopathic, occur in post term infants);
Rapid descent of fetal presenting part or end of second stage labor with fetal head
compression: after administration of intrathecal opioids or local state
Causes of fetal tachycardia
c/b developing acidemia; maternal or fetal infections; cardiac arrhythmia of epinephrine;
idiopathic; beta-mimetic drug admin or ephedrine; Rate: fetal tachycardia secondary to
fetal anemia/blood loss/abnormal fetal conduction/maternal hyperthyroidism
Causes of early deceleration
COMPLETE SOLUTIONS VERIFIED LATEST UPDATE
Define Baseline FHR
Mean FHR rounded to increments of 5 bpm during a 10 minute window; (excluding
accelerations or decelerations, or periods of marked FHR variability)
Define fetal bradycardia
FHR <60
Define fetal tachycardia
FHR >160
Define baseline FHR variability
Determined in a 10 minute window excluding accelerations and decelerations;
fluctuations in BL FHR that are irregular in amplitude and frequency; no distinction
between short term and long term, visually determined as a unit;
Quantitated as the amplitude between peak-to-trough
Absent: undetectable
Minimal: detectable but equal to or less than 5 bpm
Moderate: 6-25 bpm
Marked: greater than 25 bpm
Define Acceleration
Abrupt increase in FHR above baseline;
After 32 weeks: greater than or equal to 15 bpm above baseline lasting at least 15
seconds and less than 2 minutes from onset to return to baseline
,Before 32 weeks: greater than or equal to 10 bpm above baseline lasting at least 10
seconds from onset to baseline
Define Early Deceleration
Symmetrical gradual decrease and return of the FHR associated with a uterine
contractions; decrease is calculated from onset to the nadir of the deceleration
Define Late Deceleration
Symmetrical gradual decrease and return of FHR associated with a uterine contraction;
delayed in timing with nadir occurring after the nadir of the contraction
Define Variable Deceleration
Abrupt decrease in FHR
Onset of the decel to the beginning of the FHR nadir of less than 30 seconds
Decrease is 15 bpm or greater and duration lasting less than 2 minutes
Associated with contraction, onset and depth, duration is commonly varied with
successive uterine contraction
Define prolonged deceleration
Decrease in FHR of 15 bpm or more, duration 2 minutes or longer but less than 10
minutes
Understand the following physiologic mechanisms responsible for normal fetal
heart rate patterns.
Sympathetic input
Sympathetic nerve fibers innervate the myocardium responding to catecholamine
stimulation by increasing the FHR
Parasympathetic input
, Matures during second trimester, mediated by the vagus nerve, becomes dominate over
sympathetic stimulation during seconds trimester leading to gradual decrease in FHR
Chemoreceptors
Sensitive to changes in the oxygen and CO2 content within the blood; increased CO2
causes chemoreceptors to signal the medulla oblongata which then signals the vagus
nerve which then slows the FHR
Baroreceptors
Detects changes in pressure; any stressful situation in the fetus then evokes the
baroreceptor reflex, which elicits selective peripheral vasoconstriction and hypertension
with a resulting bradycardia
Causes of fetal bradycardia
Bradycardia : two types (aspysxia and non-asphyxial
Asphyxia causes; prolapse cord, placental abruption, uterine prolapse, vasa-p nything
<60 bpm is an emergency
Non-asphyxial causes: fetal heart block; maternal hypothermia; mild bradycardia
(idiopathic, occur in post term infants);
Rapid descent of fetal presenting part or end of second stage labor with fetal head
compression: after administration of intrathecal opioids or local state
Causes of fetal tachycardia
c/b developing acidemia; maternal or fetal infections; cardiac arrhythmia of epinephrine;
idiopathic; beta-mimetic drug admin or ephedrine; Rate: fetal tachycardia secondary to
fetal anemia/blood loss/abnormal fetal conduction/maternal hyperthyroidism
Causes of early deceleration
