This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CVS Embryology, Subject name: Anatomy
Anatomical closure of ductus aeriosus gets completed by: 
Select and explain. 
A. 2 weeks, B. 4 weeks, C. 12 weeks, D. 16 weeks
C: 12 weeks
Answer: C: 12 weeks 
Explanation: Under normal conditions, the ductus aeriosus closes functionally contraction of its muscular valve. Anatomical closure usually completed by intimal proliferation and takes 1 - 3 months i.e. by 3 month / 12 weeks ductus aeriosus should not remain patent. A patent ductus aeriosus is one of the most frequently occurring abnormalities of the great vessels (8/ 10, 000 bih)