NM704 Exam 2: Questions & Expert Verified Solutions
Define Baseline FHR Right Ans - 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 Right Ans - FHR <60
Define fetal tachycardia Right Ans - FHR >160
Define baseline FHR variability Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - 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. Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - Head compression
Causes of late deceleration with or without variability Right Ans - Due to
uteroplacental insufficiency: maternal hypotensive disorder (can be acute)
, diabetes, hyperthyroidism, autoimmune (lupus), abnormal placentation, post-
dates or maturity, uterine tachysystole (acute), fetal anemia due to RH
isoimmunization, non-immune hydrops, fetal-maternal hemorrhage
Causes of variable decelerations Right Ans - Due to cord compression
(nuchal shoulder, body or hand)
Association between variables and fetal acidemia depends on the frequency,
depth and duration along with the associate gren
causes of minimal variability Right Ans - Without decelerations it has no
correlation with fetal acidemia; sleep cycle; admin of medications such as
opiates, promethazine, beta-adrenergic agents such as terbutaline)
Causes of absent variability Right Ans - Without decelerations can be
idiopathic and not consistently associated with anemia. Evolution of moderate
to minimal to absent variables with presence of recurrent decels that are
becoming progressively deeper is class pattern evolution that reflects
developing fetal acidemia over time
causes of sinusoidal pattern Right Ans - Seen with significant anemia (i.e.
with maternal fetal hemorrhage following was vasa previa (uterine rupture)
or placental abruption; anemia secondary to RH isoimmunization; may appear
shortly before death in severely asphyxiated fetus
Meaning of Category II tracing Right Ans - Normal
Associated with normal acid-base status; well oxygenated fetus
Meaning of Category II tracing Right Ans - Indeterminate
Does not meet criteria for Category 1 or 3; not predictive of abnormal fetal
acid-base status
Meaning of Category III tracing Right Ans - Predictive of abnormal fetal
acid base status
Requires urgent/emergent evaluation of fetal strip
Preparations for emergency cesarean or operative vaginal assisted delivery
(vacuum, forceps)
Absolute rules for categories I, II, III Right Ans - ALL category 1 tracings
have moderate variability
Define Baseline FHR Right Ans - 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 Right Ans - FHR <60
Define fetal tachycardia Right Ans - FHR >160
Define baseline FHR variability Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - 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. Right Ans - 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 Right Ans - 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 Right Ans - 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 Right Ans - Head compression
Causes of late deceleration with or without variability Right Ans - Due to
uteroplacental insufficiency: maternal hypotensive disorder (can be acute)
, diabetes, hyperthyroidism, autoimmune (lupus), abnormal placentation, post-
dates or maturity, uterine tachysystole (acute), fetal anemia due to RH
isoimmunization, non-immune hydrops, fetal-maternal hemorrhage
Causes of variable decelerations Right Ans - Due to cord compression
(nuchal shoulder, body or hand)
Association between variables and fetal acidemia depends on the frequency,
depth and duration along with the associate gren
causes of minimal variability Right Ans - Without decelerations it has no
correlation with fetal acidemia; sleep cycle; admin of medications such as
opiates, promethazine, beta-adrenergic agents such as terbutaline)
Causes of absent variability Right Ans - Without decelerations can be
idiopathic and not consistently associated with anemia. Evolution of moderate
to minimal to absent variables with presence of recurrent decels that are
becoming progressively deeper is class pattern evolution that reflects
developing fetal acidemia over time
causes of sinusoidal pattern Right Ans - Seen with significant anemia (i.e.
with maternal fetal hemorrhage following was vasa previa (uterine rupture)
or placental abruption; anemia secondary to RH isoimmunization; may appear
shortly before death in severely asphyxiated fetus
Meaning of Category II tracing Right Ans - Normal
Associated with normal acid-base status; well oxygenated fetus
Meaning of Category II tracing Right Ans - Indeterminate
Does not meet criteria for Category 1 or 3; not predictive of abnormal fetal
acid-base status
Meaning of Category III tracing Right Ans - Predictive of abnormal fetal
acid base status
Requires urgent/emergent evaluation of fetal strip
Preparations for emergency cesarean or operative vaginal assisted delivery
(vacuum, forceps)
Absolute rules for categories I, II, III Right Ans - ALL category 1 tracings
have moderate variability
