Arrhythmias in the Fetus

Fetal arrhythmias occur in 1% to 3% of pregnancies. Although they have historically been challenging to diagnose, newer technologies such as fetal magnetocardiography (fMCG) have improved our understanding and diagnosis of fetal arrhythmias. fMCG has helped with identification of "silent arrhythmias," which are conduction abnormalities that are not detectable on routine obstetric and fetal echocardiography studies but can be associated with high fetal mortality. Not all fetal arrhythmias require medical management, and transplacental therapy is the mainstay of medication delivery when needed. When managing fetal arrhythmias, collaboration among obstetric, neonatology, and cardiology teams is essential to provide optimal care.