umbilical artery
Medical/anatomical term for the paired arteries that carry deoxygenated blood from the fetus to the placenta.
The umbilical artery is one of the blood vessels connecting the fetus and the placenta.
Compound of 臍 (さい, 'navel') + 動脈 (どうみゃく, 'artery'). The reading さい for 臍 is the on'yomi used in medical compounds.