Isolated Aberrant Right Subclavian Artery Detected Prenatally In a Low-Risk Primigravida: A Case Report

Abstract

Background: Aberrant right subclavian artery (ARSA) is the most common aortic arch variant increasingly recognised during routine fetal echocardiography. Although historically linked to chromosomal abnormalities, emerging evidence shows that isolated ARSA in screen-negative pregnancies has a favourable prognosis.
Case: We report a 24-year-old primigravida with a normal Level II ultrasound and a negative quadruple screening test. A routine fetal echocardiogram at 24 weeks demonstrated an isolated ARSA without any other cardiac or extracardiac anomalies. Pregnancy and delivery were
uneventful. Postnatal echocardiography confirmed isolated ARSA, and the neonate remained asymptomatic.
Conclusion: When identified as an isolated finding in the setting of normal aneuploidy screening, ARSA represents a benign vascular variant with excellent perinatal outcomes. Comprehensive counselling helps avoid unnecessary invasive testing and parental anxiety.