Key Points
- To review the efficacy, administration routes, and outcomes of in utero antiarrhythmic drug therapies for fetuses with life-threatening dysrhythmias and heart failure.
- Review of clinical case literature on transplacental maternal drug administration for managing persistent fetal dysrhythmias.
- Evaluation of secondary interventional routes, including direct fetal intramuscular injection and umbilical vein infusion, when maternal therapy fails.
- Transplacental pharmacotherapy—most frequently using digitalis—effectively cardioverts dysrhythmias and mitigates intrauterine heart failure across multiple documented presentations.
- Direct drug delivery via umbilical vein or intramuscular routes provides an alternative therapeutic pathway when maternal-fetal transfer fails to resolve persistent arrhythmias.
- Fetal survival rates remain heterogeneous, with poor outcomes occurring in fetuses developing hydrops or harboring concurrent structural heart disease.
Structured PICO
Does intrauterine drug therapy improve outcomes in fetuses with significant arrhythmias?
PPopulationFetuses with significant arrhythmias or intrauterine heart failure considered too immature for delivery
IInterventionIntrauterine drug therapy (transplacental administration of antiarrhythmic agents such as digitalis, or direct fetal therapy by intramuscular injection or umbilical vein infusion)
OOutcomeNormalizing fetal heart rate and rhythm, and abolishing or preventing fetal cardiac failure
Intrauterine antiarrhythmic therapy, primarily via transplacental administration, is a viable treatment for fetal arrhythmias to prevent heart failure and improve survival.