The fetal ductus arteriosus and its abnormalities--a review.

The ductus arteriosus (DA) is a small vessel with major functional importance for the integrity of the fetal circulation. Technical advances in prenatal diagnostics facilitate appropriate echocardiographic estimation of the ductal flow and its abnormalities. Despite the emerging knowledge of its embryological background and developmental processes during advancing gestation we still have to face unresolved questions regarding the identification and optimal surveillance of fetuses at risk of premature closure of the ductus. Prenatal administration of tocolytics such as indomethacin should be monitored by close Doppler sonographic scans to follow the ductal circulation. Understanding the transcriptional regulation of normal DA development, maturation, and closure of the arterial duct as well as the hemodynamic changes during pregnancy and after delivery may provide additional targets for rational drug design to either close or open the DA, both antenatally and postnatally.