Abstract

The Ductus Arteriosus is a vascular structure that is responsible for the union of the pulmonary artery with the descending aorta during fetal life. At the time of birth, with the beginning of breathing and separation of the placenta, the ductus is closed. This closure is carried out in two phases. During the first twelve hours of life, contraction and migration of the smooth muscle of the duct occurs, which causes a longitudinal shortening and a circumferential narrowing. This process generates an occlusion of the vascular structure that occurs at functional closure. At 2-3 weeks of age, the fibrosis phase of the medial and intimal layers is terminated and the ductus arteriosus is closed. It is estimated that in 90% of full-term newborns, the ductus arteriosus is closed at eight days of age.