OC101: Fetal aberrant right subclavian artery in normal fetuses and in Down syndrome

Abstract

To evaluate the prevalence of fetal aberrant right subclavian artery (ARSA) in a low-risk population and compare with the rate of its appearance among Down syndrome (DS) fetuses, and to estimate its potential as a marker in DS screening. This was a cross-sectional sonographic study. Women attending routine fetal sonographic examination between 13 and 26 weeks of gestation were evaluated for the presence of an ARSA using either a transvaginal multifrequency 5–9-MHz probe or transabdominal 4–8-MHz probe as appropriate. Early pregnancy outcome was obtained in all cases. Nine hundred and twenty-four fetuses were recruited. ARSA was detected in 13 fetuses (1.41%) with normal karyotype. During the study period, eight fetuses referred either with known karyotype or with signs suspicious of DS were evaluated by the same protocol. Three of eight fetuses (37.5%) were found to have ARSA. In none of these cases was ARSA an isolated finding. The odds ratio for ARSA in DS vs. normal fetuses was 41.9 (95% CI, 8.9–195). ARSA was found in 1.41% of the normal population. In this study we observed a trend toward a higher rate of ARSA among DS fetuses. In none of these was ARSA an isolated finding. Larger prospective studies are needed to test the strength of this marker as an adjunct tool in DS screening and risk assessment.