Which of the following is a stimulus for closure of ductus arteriosus?: (A) Increased O2 tension, (B) Hypoxia, (C) Prematurity, (D) Hypercapnia
Answer is A. a. Increased O2 tension(Ref: Nelson's 20/e p 2162)In the course of several days after birth, the high arterial Po2 constricts and eventually closes the ductus arteriosus, which eventually becomes the ligamentum arteriosum