We describe a rare instance of isolated pulmonary regurgitation caused by a
dysplastic pulmonary valve which was detected prenatally. Fetal echocardio
graphy demonstrated severe pulmonary regurgitation, and progressive cardiom
egaly because of right ventricular volume overload. After birth, conservati
ve therapy was successful in alleviating the pulmonary vascular resistance,
and the pulmonary regurgitation gradually decreased.