In a healthy newborn soon after delivery, there is constriction of the ductus arteriosus. This process is most likely influenced by which of the following changes?

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Quizplus · Accepted Answer

The constriction of the ductus arteriosus in a newborn is primarily influenced by a decrease in serum prostaglandin concentration, which occurs after birth as the placenta is removed and the newborn begins to breathe air.  Due to the vasodilating action of PGE 1, it is used pharmaceutically as alprostadil to treat newborn infants with ductal-dependent congenital heart disease. The administration of alprostadil in these infants maintains a patent ductus arteriosus until surgery can be carried out to correct the underlying heart defect. Ductus arteriosus is a normal structure of the fetal heart that allows blood to bypass circulation to the lungs since the fetus does not use his/her lungs in utero. The ductus arteriosus shunts blood flow from the left pulmonary artery to the aorta. Shortly after birth, the ductus closes due to the high levels of oxygen the newborn is exposed to at birth. However, in newborns with certain congenital heart defects, maintaining a patent ductus arteriosus is clinically significant.

In a Healthy Newborn Soon After Delivery, There Is Constriction