The fetal ductus arteriosus, a review.

The developmental biology of the human ductus arteriosus is reviewed from its origins in the 6th branchial arch to its ultimate closure and obliteration in the neonatal period. Different concepts of ductal maturation are discussed and the role of prostaglandins in this process are highlighted. Recent advances in Doppler ultrasound have made it possible to observe and measure fetal ductus arteriosus blood flow as early as 11 weeks of gestation. During indomethacin tocolysis ductal constriction can be monitored with Doppler ultrasound in order to stop indomethacin administration when necessary, thus making indomethacin tocolysis safer.