Arterial anastomosis in the pregnant human uterus.

A plastic-cast technique was used to study the arterial vascular tree of the human uterus during pregnancy. The 3-dimensional models thus obtained revealed the organization, distribution, number, and diameter of the vessels. A vast ipsilateral and contralateral anastomotic network was evident throughout the uterus. The vascular structure reveals an increase in the size and degree of arborization of the arcuate arteries in and around the implantation site, which developed as a result of the increasing demand emanating from it.