Single umbilical artery: fetal and placental histopathological analysis of 24 cases.

Aim: 24 cases of single umbilical artery (SUA) are presented and the related histopathological findings of the fetuses and placentas examined. SUA is the most common congenital anomaly of the umbilical cord, resulting in the absence of one of the two umbilical arteries. It has an incidence of approximately 2.