Diagnosis, Risk Factors, and Management Principles of Fetal Premature Atrial Contractions.

Fetal premature atrial contractions (PACs) are the most common fetal arrhythmia, accounting for up to 90% of cases. Although predominantly benign and self-limiting, PACs carry a small but significant risk of adverse outcomes, including progression to supraventricular tachycardia (SVT), and heart failure. This review synthesizes current evidence on the epidemiology, etiology, and risk stratification of fetal PACs. We highlight the importance of M-mode and Doppler echocardiography in diagnosis and in distinguishing PACs from atrioventricular block (AVB). A risk-stratified management pathway is proposed: low-risk cases (isolated PACs, normal ventricular rate, no structural abnormalities) require weekly heart rate monitoring and routine obstetric care; high-risk cases-characterized by blocked PACs, bigeminy/trigeminy, frequent PACs, bursts of tachycardia, atrial septal aneurysm, heart failure, or associated congenital heart disease-warrant enhanced surveillance, multidisciplinary consultation, and consideration of antiarrhythmic therapy or timely delivery. Postnatal follow-up is essential to confirm resolution and manage late-onset SVT. Accurate diagnosis and risk-adapted intervention are critical to optimizing perinatal outcomes.