Aberrant right subclavian artery (ARSA) in unselected population at first and second trimester ultrasonography

Abstract

Prenatal routine US assessment of the RSA is feasible by highly experienced operators in first trimester screening. There is an important association of ARSA detected in unselected population with fetal abnormalities, including aneuploidies, cardiac defects and genetic anomalies. In trisomy 21 fetuses, ARSA can be the only first trimester US marker or, when associated to increased NT, it can represent the only 'additional' marker.