Pelvic venous disorders
Pelvic venous disorders – problems with the veins in the pelvic area – can cause chronic pelvic pain.
Veins are blood vessels that carry blood from the body back to the heart. Sometimes the valves in the pelvic or abdominal veins do not work properly and blood may flow in the wrong direction (reflux). Or there may be a blockage (obstruction) in the veins. Both of these situations can cause the blood to build up in the pelvic veins. When this happens, the veins in your pelvis can enlarge and change shape, like varicose veins. This can cause chronic pelvic pain and other symptoms.
These conditions happen mostly in women of childbearing age and may be more common in women who have given birth to more than one child.
A pelvic or abdominal vein obstruction or reflux can lead to many symptoms, such as unexplained leg pain or swelling, pelvic pain, or leg ulcers that won't heal.
Some patients with a pelvic vein disorders experience little leg pain or swelling but do experience pelvic pain. It may come and go or be constant. The pain may vary from mild to severe.
Pelvic/abdominal vein disorders can also cause pain during or after intercourse (dyspareunia).
These symptoms may be worse after exercise because of the increased flow of blood into the legs. Pelvic pain may also happen as other veins enlarge to carry blood around the blocked veins.
The most common cause of pelvic vein obstruction is compression of the iliac vein as it carries blood out of the leg and pelvis. Iliac vein compression often happens when the vein is squeezed between the iliac artery and the spine. Other causes of compression may include an ovarian or uterine cyst or growth or, occasionally, cancer in the pelvis or abdomen.
Pelvic vein obstruction can also happen in those who have had previous clotting (deep vein thrombosis) involving the iliac veins. A deep vein thrombosis may result in complete obstruction of the iliac veins. Or, it may lead to partial obstruction as the clot partially resolves, leaving behind a narrowed vein or webs within the vein that limit blood flow back to the heart.
A few patients develop obstruction of the inferior vena cava (IVC), the larger vein that passes in the deep abdomen from about the level of the navel (umbilicus) to the heart. Most obstructions of IVC are due to clotting and/or scarring at the site of an IVC filter. This is small metallic device implanted by a needle stick through the groin or neck into the IVC at the mid-abdomen. It prevents large clots (thrombi) from moving to the lungs where they can block blood flow. Other causes of IVC obstruction include extensive clotting (venous thrombosis) or tumor growth.