abdominal pain (often left-sided)
increased menstrual cramps
pain in the genitals
pain during bowel movements
urination and painful urination
congestion in the genital area (especially in women who had multiple births)
varicose veins in the groin and on the external genitalia
In pelvic congestion, pain in the lower abdomen or in the left testicle results from the diversion of blood from the left kidney to the organs of the pelvis. This blood is drained via the ascending lumbar vein and the left ovarian (in males*: spermatic) vein into the pelvis. This additional volume needs to be transported to the inferior vena cava, which runs at the right side of the spine. Within the pelvis a vast network of veins fills the space between the organs, mainly the uterus (prostate*), rectum, urinary bladder and vagina. This network takes up the renal blood from the left kidney but may soon be overfilled. If so, complaints emerge. These consist mainly of painful sensations at rest, during voiding, bowel movements, menstruation or sexual intercourse. Sometimes bleeding occurs from the hemorrhoidal venous plexus of the anus, sometimes bloody urine is observed. Voiding may be very urgent and frequent resulting in little amounts of urine only. This situation is very often misinterpreted as urinary bladder inflammation, infection or pyelonephritis, especially since red blood cells are often found in the urine, but white blood cells, characteristic for all kinds of inflammation, are missing.
The pressure in the deep pelvic veins may rise to an amount that the main left sided pelvic vein, the left common iliac vein may be filled mainly by the blood coming from the left kidney. Since the left common iliac vein also takes up blood from the left leg, via the left external iliac vein, this blood may be partially blocked. A congestion of the left leg, left thigh and the left parts of the genitalia results. In women with multiple pregnancies, varices of the left groin, tenderness and pain may result. Sometimes a fullness of the clitoris and the labia majora and minora with unsolicited sexual arousal occurs and may be bothering. Thrombosis of the deep veins of the left leg, mainly of the calf, and varices of the left leg may develop.
To get access to the inferior vena cava, left renal blood is thus pressed partly across deep veins of the pelvic plexus, partly across the left common iliac vein. But this large vessel may also be blocked in persons who have a strong lumbar lordosis. In this case the promontory is especially prominent and sticks out frontally into the pelvis from behind. This compression of the left common iliac vein by the overlying right common iliac artery against the promontory is known, after its first description by two Swiss physicians, as May-Thurner-constellation.