Umbilical a.

Umbilical arteries supply deoxygenated blood from the fetus to the placenta in the umbilical cord. There are usually two umbilical arteries present together with one umbilical vein in the cord. The umbilical arteries are branches of the internal iliac arteries. 

The umbilical arteries are the only arteries in the human body, aside from the pulmonary arteries, that carry deoxygenated blood.

Inside the placenta, the umbilical arteries connect with each other at a distance of approximately 5 mm from the cord insertion. Subsequently, they branch into chorionic arteries or intraplacental fetal arteries.