Best practice guidelines: fetal surgery.

Fetal intervention encompasses a range of procedures on the fetus with congenital structural anomalies, whilst still on the placental circulation. The concept of fetal surgery was conceived in order to prevent fetal or early postnatal death, or to prevent permanent irreversible organ damage. The benefit of these procedures has to be balanced with risks to both the mother and the fetus.

Absence of the ductus venosus.

Absence of the ductus venosus is a rare vascular anomaly, but clinicians should be aware that it can be diagnosed antenatally and the prognosis is dependent on the type of associated malformation of the fetal vascular system. Antenatal detection of a single umbilical artery and unexplained cardiomegaly should prompt detailed examination of the umbilical and portal veins. Absent ductus venosus is associated with three main patterns of abnormal venous circulation, the worst prognosis being seen when the umbilical vein bypasses the liver and connects to the right atrium.