Fetal Aberrant Subclavian Artery: A Retrospective Evaluation of Prenatal Findings and Postnatal Prognosis

Background/Aims: To evaluate the prenatal characteristics, associated anomalies, and postnatal outcomes of fetuses diagnosed with aberrant right subclavian artery (ARSA) during routine obstetric ultrasonography. Methods: This retrospective study included 39 fetuses diagnosed with ARSA between 2022 and 2025 at a tertiary perinatology clinic. Prenatal ultrasound findings, results of genetic testing, and postnatal unfavourable outcomes—including neonatal intensive care admission, dysphagia, respiratory symptoms, and the need for surgical intervention—were investigated. Results: ARSA was an isolated finding in 64.1% of fetuses, while 35.9% had additional anomalies, most commonly single umbilical artery (28.6%), intracardiac echogenic focus (21.4%), and polyhydramnios (21.4%). Amniocentesis was performed in 28.2% of cases, with trisomy 21 identified in one fetus presenting with multiple anomalies. Of all cases, 97.4% resulted in live births. Postnatal unfavourable outcomes presented in 12.8% of cases, and 15.4% required neonatal intensive care. Among those fetuses with unfavorable outcomes, all but one had additional prenatal anomalies. Conclusions: Isolated ARSA is generally associated with a favorable prognosis and should be considered a soft marker without other sonographic abnormalities. However, the presence of additional structural findings significantly increases the risk of genetic and postnatal negative outcomes, underscoring the importance of comprehensive prenatal evaluation and multidisciplinary counseling.