Fetal supraventricular tachycardia and hydrops fetalis: combined intensive, direct, and transplacental therapy.

A 25-week fetus with severe hydrops fetalis secondary to supraventricular tachycardia was treated with fetal intramuscular injections of digoxin in conjunction with maternal intravenous digoxin, followed by oral digoxin and subsequently by oral procainamide therapy. Fetal umbilical blood sampling revealed poor placental transfer of digoxin, even after 2 weeks of therapeutic maternal levels. This case suggests that direct fetal therapy is of value in the treatment of some fetuses with supraventricular tachycardia, and lends further evidence that the role of transplacental digoxin therapy is limited in the compromised fetus. It also demonstrates that resolution of hydrops may require a prolonged period.