Abstract
Eleven cases of single umbilical artery are described. They were encountered among 411 autopsies on stillborn and live-born babies under 8 weeks of age. Nine had severe associated congenital malformations involving particularly the urinary tract. Absence of an umbilical artery can be diagnosed by simple examination of the cord at birth. In the absence of severe external malformations, such an infant has a 2:1 risk of internal malformations which may require early surgical treatment.