ductus arteriosis

https://doi.org/10.1351/goldbook.10618

Fetal blood vessel connecting the pulmonary artery to the proximal descending aorta.

Note: This vessel allows most of the blood from the right ventricle to bypass the fetus’s fluid-filled non-functioning lungs. Upon closure at birth, it becomes the ligamentum arteriosum.
Source:
PAC, 2016, 88, 713. (Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)) on page 745 [Terms] [Paper]