What causes closure of the foramen ovale at birth?
A) Higher pressure in the left atrium, which causes interatrial septum flaps to close
B) Rapid myocardial tissue growth stimulated by pregnancy hormones
C) A rise in fetal oxygen levels, which triggers growth of the epithelial lining
D) An increase in endothelial mucous production, which forms a plug
E) Migration of connective tissue from the right atrioventricular valve

Question

Quizplus · Accepted Answer

At birth, the pressure in the left atrium becomes higher than in the right atrium due to the initiation of lung function, causing the septum primum to press against the septum secundum, closing the foramen ovale.

What Causes Closure of the Foramen Ovale at Birth