Prostaglandins and the ductus arteriosus.

Fetal patency of the ductus arteriosus is an active state maintained by the relaxant action of a prostaglandin, most probably prostaglandin E2. This PG mechanism is most active in the immature ductus and decreases toward term. The ductus closes when this prostaglandin effect if withdrawn. Indomethacin may induce closure of the patent ductus arteriosus of prematurity. It is most likely to be successful if given intravenously and early in postnatal life. Prostaglandin E1, to maintain patency of the ductus, is now established in the emergency management of several congenital heart defects causing problems in the newborn.