Baroreceptors are stimulated by increased arterial pressure and cause which fetal heart rate response?

• A. Increased heart rate
• B. Decreased heart rate
• C. No change in heart rate
• D. Variable change in heart rate

Answer: (B)

Baroreceptors sense stretch in the arterial walls. When they detect an increase in arterial pressure, they increase their firing, signaling the brainstem to boost parasympathetic (vagal) activity to the heart and temper sympathetic input. This shift slows the SA node firing, producing a decrease in fetal heart rate. So the normal reflex to higher arterial pressure is bradycardia. Increased heart rate would come from sympathetic activation during low pressure, no change would imply no reflex, and a variable change isn’t a consistent response to elevated pressure.