Hydralazine is best described as which type of agent, and what maternal-fetal effect is noted?

• A. A smooth muscle vasodilator; may cause fetal bradycardia and uteroplacental insufficiency due to maternal hypotension
• B. A beta-adrenergic agonist; improves fetal heart rate
• C. A calcium channel blocker; increases fetal distress risk
• D. An ACE inhibitor; causes fetal renal impairment

Answer: (A)

Hydralazine acts as a direct-acting arteriolar vasodilator, relaxing smooth muscle in the vascular wall to rapidly lower systemic vascular resistance and blood pressure. In pregnancy, this maternal blood pressure drop can reduce uteroplacental perfusion, leading to fetal distress such as fetal bradycardia and uteroplacental insufficiency. It’s not a beta-adrenergic agonist, not a calcium channel blocker, and not an ACE inhibitor—those classifications and their fetal effects don’t apply to hydralazine.