Coarctation of the aorta is often considered a critical congenital heart defect (critical CHD) because if the narrowing is severe enough and it is not diagnosed, the baby may have serious problems soon after birth. CCHDs also can be detected with newborn pulse oximetry screening. Pulse oximetry is a simple bedside test to determine the amount …

https://www.cdc.gov/ncbddd/heartdefects/coarctationofaorta.html