Pediatrics Which of the following is the main factor for the ductal closure postnatally A Increase in paial pressure of oxygen (PaO2) B Increase in systemic vascular resistance C Increase in circulating prostaglandin levels D Decrease in pulmonary venous resistance 💡 Explanation Which of the following is the main factor for the ductal closure postnatally ✓ Correct Answer: A. Increase in paial pressure of oxygen (PaO2)