A 25-year-old pregnant woman was admitted with frequent episodes of supraventricular tachycardia associated with Wolf-Parkinson-White syndrome. She was treated acutely with adenosine therapy during induction of labor and post-partum. Generally, pharmacologic treatment should be undertaken only for symptomatic arrhythmias or in hemodynamically compromised patients. Adenosine is the first choice for acute treatment of supraventricular tachycardia in pregnancy; several other options exist, but all have the potential for negative side effects for mother and fetus. Direct-current cardioversion is acceptable in all stages of pregnancy.