Prostaglandins are used to maintain patency of which structure in neonates?

• A. Foramen ovale
• B. Aorta
• C. Ductus arteriosus
• D. Pulmonary artery

Answer: (C)

Prostaglandins keep the ductus arteriosus open. In fetal life, the ductus arteriosus links the pulmonary artery to the aorta, allowing blood to bypass the non-functioning lungs. After birth, it normally constricts and closes as oxygenation begins. In certain newborns with duct-dependent congenital heart defects, we use prostaglandin E1 to keep this vessel patent so that blood can flow to the rest of the body or to the lungs until corrective surgery. The mechanism is that prostaglandin E1 relaxes the smooth muscle of the ductus arteriosus by increasing cyclic AMP, preventing normal closure. The other options are structures that don’t require prostaglandin-driven patency for standard neonatal management: the foramen ovale is the fetal interatrial opening that also closes after birth, and the aorta and pulmonary artery are major vessels whose patency isn’t maintained by prostaglandins in this context.