umbilical veins (changes after birth)
Last reviewed 01/2018
The left umbilical vein obliterates after birth and after the umbilical arteries have closed, although the vein may be used as a conduit for infusion in the immediate neonatal period. Closure occurs by thrombosis within the lumen and mechanical stimuli causing spasm of the muscular wall.
After birth, the umbilical vein forms the ligamentum teres.