The discovery of a right-sided aortic arch during a fetal screening ultrasound or cardiac ultrasound often makes parents-to-be nervous about how this will affect their child in the future. The following are some of the details. The vast majority of aortic arches are on the left side of the trachea and esophagus. The right aortic arch, as the name implies, is located on the right side of the trachea and esophagus, in which case the aortic arch travels backward and to the left, connecting to the descending aorta, which is located on the left side of the spine. The direction of the branches of the cephalic vessels emanating from the right aortic arch are in mirror image relationship to the branches of the normal aortic arch. In the right aortic arch, if a left arterial duct (which closes after birth to become an arterial ligament) is emitted from the descending aorta, or if a left subclavian artery (i.e., vagal left subclavian artery) is emitted, the arterial duct and left subclavian artery will travel to the left after the esophagus, thus forming a complete circumferential vascular structure in space with the right aortic arch, encircling the trachea and esophagus, which may compress the trachea and esophagus This is known as a “vascular ring” and is associated with respiratory distress, wheezing and recurrent respiratory infections, swallowing difficulties, slow feeding and stunted growth. In an article published this year in the British journal Heart, 98 fetuses with right-sided aortic arch diagnosed by prenatal echocardiography at a tertiary care center between 2004 and 2012 were followed up after birth. The results showed that 71 cases (81.6%) had combined congenital heart disease, 31.6% had malformations of organs other than the heart, and 15% had combined chromosomal abnormalities. A vascular ring was diagnosed in 12 cases (12.2%) after birth. The incidence of congenital heart disease was also higher in those with a combination of both extracardiac malformations and chromosomal abnormalities. 10.3% of the cases that died in the first year of life were children with combined congenital heart disease. Therefore, for right-sided aortic arch found in fetus, it is necessary to first carefully confirm whether it is combined with heart or other organ malformation. If congenital heart disease is combined, then there is a higher chance that chromosomal abnormalities will also be combined, and the future condition of the child will depend largely on the severity of the congenital heart disease and extracardiac malformations. An “isolated” right aortic arch with no combined intracardiac or extracardiac anomalies has a lower risk of combined chromosomal abnormalities. Because the right aortic arch causes a looser vascular ring, the majority of cases do not compress the trachea or esophagus, which is a normal anatomic variant and does not require management. In the few cases that do cause compression, symptoms generally appear relatively late compared to other types of vascular rings, mostly after the age of 1 year; symptoms are relatively mild, and in some cases can be reduced or relieved as the child grows. However, if the symptoms of compression appear within 6 months of the child’s birth, it suggests that the condition is often more severe and requires aggressive treatment. Treatment is surgical removal of the ductus arteriosus or ligamentum arteriosum. The vagus left subclavian artery usually does not need to be disposed of, but if there is aneurysmal dilatation of its root, there is a risk of severe tracheoesophageal compression, which needs to be treated together. Surgical results are generally better.