Patent Ductus Arteriosus, Prematurity, and Respiratory Distress Syndrome

To the Editor.— The finding by the Birth Defects Monitoring Program of the Centers for Disease Control1that patent ductus arteriosus was the most common major malformation in minority groups and the second most common in whites deviates greatly from data published previously. Fyler2found patent ductus arteriosus to be only the sixth most common congenital heart defect; Mitchell et al3listed patent ductus arteriosus as the third most common heart defect. Both studies reported ventricular septal defects to be two to four times more frequent than patent ductus arteriosus. Explanation of the discrepancy undoubtedly lies in the probability that in the Birth Defects Monitoring Program study the discharge diagnosis of patent ductus arteriosus was made mostly in premature infants whose ductus remained open in the neonatal period secondary to their immaturity and to metabolic abnormalities accompanying the respiratory distress syndrome. In these circumstances, patent ductus arteriosus