Background: Congenital hepatic arteriovenous malformations complicated by high-output heart failure and hematologic derangements are associated with up to 90% mortality. Prenatal diagnosis alerts the pediatrician to the need for early neonatal intervention. Case: A fetal hepatic arteriovenous malformation with associated high-output cardiac failure was diagnosed at 29 weeks' gestation using real-time and color flow Doppler sonography. Hydrocortisone injected directly into the umbilical vein and the amniotic sac resulted in appreciable improvement in hemodynamic and hematologic indices. The pregnancy ended in a preterm delivery at 31 weeks with no evidence of heart failure at birth. Conclusion: The compromised preterm fetus with a hepatic arteriovenous malformation can be treated in utero, avoiding early emergency delivery.