COMPLETE QUESTIONS WITH ACCURATE
ANSWERS
◉ early decelerations are considered clinically...
Answer: benign
◉ what is physiologic mechanism of early declerations?
Answer: transient fetal head compression → ↑ intracranial
pressure/alteration in cerebral blood flow → reflex parasympathetic
outflow/vagal stimulation → gradual slowing of the FHR → early
deceleration → when head compression is relieved, autonomic
reflexes subside
◉ what is a variable deceleration?
Answer: an abrupt decrease in fetal heart rate (onset to nadir < 30
seconds); decrease is > 15 bpm from baseline lasting > 15 seconds
and < 2 minutes from onset to return to baseline
not necessarily associated with uterine contraction
◉ what does a variable deceleration represent?
Answer: a reflex fetal response to interruption of the oxygen
pathway at one or more points
, ◉ what is the physiologic mechanism of a variable deceleration?
Answer: umbilical cord compression → initial compression of
umbilical vein → transient decreased fetal venous return → transient
reduction in fetal cardiac output and blood pressure → baroreceptor
stimulation → transient reflex rise in FHR → umbilical artery
compression → abrupt rise in fetal peripheral resistance and blood
pressure → baroreceptor stimulation → reflex parasympathetic
outflow → abrupt slowing of the FHR → variable deceleration →
when umbilical cord compression is relieved, this process occurs in
reverse
◉ what is a late deceleration?
Answer: visually apparent, gradual decrease and return of the FHR
associated with a uterine contraction (onset to nadir > 30 seconds)
delayed in timing with nadir of decel occurring after the peak of the
contraction
◉ what does a late deceleration represent?
Answer: reflex fetal response to transient interruption of the oxygen
pathway at one or more points during a uterine contraction,
resulting in transient fetal hypoxemia
◉ late decelerations result from...