The ovarian vein is a blood vessel that drains blood from the ovaries, which are part of the female reproductive system. Each ovary has its own ovarian vein, which carries deoxygenated blood back to the heart. The right ovarian vein typically drains into the inferior vena cava, while the left ovarian vein drains into the left renal vein. These veins play a crucial role in maintaining proper blood flow and hormonal balance in the body. They are also important in the context of certain medical conditions, such as ovarian torsion or pelvic congestion syndrome, where issues with blood flow can lead to pain and other complications.