Right ductus arteriosus: Facts and theory

Objective: To report fetal right-sided persistent ductus arteriosus (RPDA) in association with right aortic arch (RAA). Study design: Extensive sonographic fetal anatomical scans were consecutively performed on 19,874 private, self-referred pregnant women who wanted early sonographic detection of fetal anomalies. Results: Of 19,874 transvaginal (TVS) sonographic examinations 40 fetuses had right aortic arch (RAA) and four of them (10%) had RPDA. We also diagnosed seven cases of RPDA with involvement of the left aortic arch where a right-curving pattern ("L" shape) parallel to the right pulmonary artery was suggestive of Rt. DA with left aortic arch. Only one (9%) of the RPDA cases was associated with a cardiac anomaly (double outlet right ventricle). None of the other eight RPDA cases had any discernible anomalies, and all of the fetuses with RPDA had normal karyotypes. Conclusions: In 10% of the fetuses with right aortic arch the ductal arch was also on the right side. An unusual-looking DA may be a RPDA associated with the left aortic arch. In most cases, the RPDA is a normal variant not associated with other anomalies.