Digoxin Therapy in the Fetus

Sir.—We read with interest the article by Wiggins et al1concerning fetal cardiac abnormalities and their in utero treatment with digoxin. Although the authors provide invaluable information on the usefulness of fetal echocardiography, we disagree with some of their conclusions concerning digoxin therapy in the fetus. Our interest in this area was sparked by a twin pregnancy complicated by twin transfusion syndrome, in which maternal administration of digoxin reversed the ultrasonographic signs of heart failure in the recipient twin.2At that time, a review of the literature for pharmacokinetic data to direct our therapy produced disappointing results. Despite multiple case reports demonstrating the benefits of digoxin in fetal heart failure caused by tachyarrhythmias, rarely was pharmacokinetic information reported, such as patient's weight (from which desired total-body glycoside stores could be determined), creatinine clearance (from which daily loss and maintenance dose is calculated), or time since last dose