Normally, a blood vessel needed only for
fetal
blood circulation
(called the ductus arteriosus) closes off at birth.
During fetal development, this blood vessel is kept open by a naturally
occurring substance in the fetus's body called prostaglandin. At birth, fetal
production of prostaglandin decreases and the ductus arteriosus closes.
In some premature infants, this blood vessel does not close, which is
a condition called a
patent (open) ductus arteriosus. These premature
infants are given a prostaglandin inhibitor, a medicine to stimulate the
closure of this blood vessel.
When an infant has certain other
congenital heart defects, a medicine (a form of
prostaglandin) is often given by vein to keep the
ductus arteriosus open. Keeping this blood vessel open allows the blood to
continue circulating until surgery or another procedure can be done to correct
the related defect and allow normal blood flow.