When assessing a newborn for retention of a fetal structure leading to a congenital heart defect, which fetal structures require change after birth?

After birth, the fetal circulatory structures must transition to accommodate the newborn's independent circulation. The foramen ovale and ductus arteriosus are two crucial structures that undergo significant changes as the newborn begins breathing air and the demands on the heart and lungs shift.

The foramen ovale is an opening between the right and left atria that allows blood to bypass the non-functioning fetal lungs. After birth, as the lungs expand and blood flow to them increases, pressure in the left atrium rises, causing the foramen ovale to close, usually within the first few months of life. Failure of this structure to close can lead to a left-to-right shunt, contributing to congenital heart defects.

The ductus arteriosus connects the pulmonary artery to the aorta, allowing blood to bypass the lungs during fetal life. With the onset of breathing, the ductus arteriosus also constricts and typically closes within the first few days or weeks after birth. If it remains patent, it can lead to increased pulmonary blood flow and pulmonary hypertension, also posing a risk for congenital heart issues.

Both the foramen ovale and ductus arteriosus must close appropriately after birth to establish normal fetal-to-neonatal circulation. Retention