Patent Ductus Arteriosus

Background 1. The ductus arteriosus is a vessel connecting the pulmonary artery to the aorta that allows blood flow to bypass the fetal lungs. 2. Decreased circulating prostaglandin concentrations and increased oxygen levels promote postnatal constriction of the ductus arteriosus; therefo

re, the failure of circulating prostaglandin concentrations to drop results in persistent patency of the ductus arteriosus. 3. Ductal constriction typically occurs within 72 hours of birth in term neonates and by 4 days in preterm neonates born older than 29 weeks’ gestation.