Pelvic Venous Thrombosis

Pelvic venous thrombosis occurs when a blood clot forms in one of the veins located in the pelvic region, blocking blood flow and potentially causing serious health complications if left untreated.

Table of contents

• What Is Pelvic Venous Thrombosis?
• Types of Pelvic Venous Thrombosis
• What Causes Pelvic Venous Thrombosis?
• Who Is at Risk?
• Signs and Symptoms
• How Is It Diagnosed?
• Treatment Options

What Is Pelvic Venous Thrombosis?

Pelvic venous thrombosis is a condition where a blood clot, also called a thrombus, develops in the veins of the pelvic area^[3]. These clots can form in different veins within the pelvis, including the deep pelvic veins and the ovarian veins. When blood clots block the flow of blood through these vessels, they can cause localized problems in the pelvis and have the potential to break loose and travel to other parts of the body, including the lungs^[3].

Blood clots in the pelvic veins are serious because they not only cause symptoms in the pelvic region but may also lead to life-threatening complications. If a clot breaks free from the pelvic vein and travels through the bloodstream, it can become lodged in a lung artery, causing a condition called pulmonary embolism^[3]. This is a medical emergency that requires immediate treatment.

Types of Pelvic Venous Thrombosis

Pelvic venous thrombosis can affect different veins in the pelvic area, and the specific type depends on which vein is involved^[3].

Deep pelvic vein thrombosis occurs when a blood clot develops in one of the deep veins in the pelvis. This type of clot may result in pelvic pain and other symptoms related to blocked blood flow in the pelvic region^[3].

Ovarian vein thrombosis is particularly common in patients who have recently given birth. This condition occurs when a blood clot forms in one of the ovarian veins, most often the right ovarian vein^[3][7]. The right ovarian vein is involved in 70 to 80 percent of cases^[7]. Symptoms typically include pelvic pain and pain in the lower abdomen. In some cases, a mass may be felt in the affected area^[3].

Septic pelvic thrombophlebitis is a rare but serious condition that occurs when an infected blood clot causes inflammation within a pelvic vein^[3]. This condition is more common in women who have delivered a baby by cesarean section rather than through natural birth. While most women recover fully with proper treatment, septic pelvic thrombophlebitis can be fatal without prompt medical attention. Symptoms include pelvic pain, back pain, fever, vomiting, nausea, chills, and sometimes a ropelike mass that can be felt in the abdomen^[3].

What Causes Pelvic Venous Thrombosis?

Pelvic venous thrombosis develops when conditions favor the formation of blood clots in the pelvic veins. Several factors can contribute to clot formation in this region^[2][7].

One of the most common causes is compression or narrowing of the pelvic veins. The most common cause of pelvic vein obstruction is compression of the iliac vein, which carries blood out of the leg and pelvis. This compression often happens when the vein is squeezed between an artery and the spine^[2]. Other causes of compression may include cysts or growths in the ovaries or uterus, and occasionally cancer in the pelvis or abdomen^[2].

Previous blood clots can also lead to pelvic venous thrombosis. When someone has had deep vein thrombosis involving the iliac veins in the past, the veins may become narrowed or scarred. This can result in complete blockage of the iliac veins, or it may lead to partial obstruction with areas inside the vein that limit blood flow back to the heart^[2].

Pregnancy is a significant risk factor for pelvic venous thrombosis. During pregnancy, the body undergoes natural changes that increase the risk of blood clots^[3]. The growing uterus puts pressure on blood vessels, particularly the large vein that carries blood from the lower body back to the heart. Blood volume also increases by up to 20 percent during pregnancy, placing a greater load on the blood vessel system^[3]. Additionally, hormone levels spike during pregnancy, causing ligaments and the smooth muscle cells inside veins to relax. This makes it harder for blood to travel upward from the legs and pelvis^[3].

The body also produces more clotting proteins during pregnancy. While this natural change helps prevent excessive bleeding during delivery, it also increases the risk of developing a blood clot in any of the veins in the pelvis^[3].

In some cases, pelvic venous thrombosis may occur in people with certain medical conditions that affect blood clotting, such as hypercoagulable conditions^[4][7]. Pelvic inflammatory disease, cancer, pelvic surgery, and inflammatory bowel disease can also increase the risk of developing pelvic venous thrombosis^[7].

Who Is at Risk?

Certain groups of people have a higher chance of developing pelvic venous thrombosis^[2][3].

Women of childbearing age are particularly at risk, especially those who have had multiple pregnancies. Pelvic venous thrombosis is most common in women aged 20 to 45^[2][5]. Weight gain, which commonly occurs during pregnancy, is also associated with increased risk^[2][5].

Women who have recently given birth are at increased risk for ovarian vein thrombosis. This condition occurs in approximately 0.05 to 0.18 percent of pregnancies^[7]. The risk is higher after cesarean delivery compared to vaginal delivery^[7].

People who have had blood clots in the past are also at higher risk for developing pelvic venous thrombosis^[2][5]. Those with inherited or acquired blood clotting disorders face increased risk as well^[4].

Signs and Symptoms

The symptoms of pelvic venous thrombosis can vary depending on which vein is affected and how severe the blockage is^[2][3].

Pelvic pain is one of the most common symptoms. The pain may be sudden and severe, or it may develop gradually over time^[4]. Some people experience constant pain, while others have pain that comes and goes^[3]. The pain may range from mild to severe^[3].

When pelvic venous thrombosis affects blood flow to the legs, it can cause unexplained leg pain or swelling^[2][3]. Some patients may develop leg ulcers that are difficult to heal^[3].

People with septic pelvic thrombophlebitis typically present with fever, along with pelvic pain, back pain, nausea, vomiting, and chills^[3]. A tender mass may be felt on physical examination of the abdomen^[3][7].

Some patients with pelvic venous thrombosis may also experience pain during or after sexual intercourse^[2].

How Is It Diagnosed?

Diagnosing pelvic venous thrombosis requires a combination of medical history, physical examination, and imaging tests^[2][5][7].

Several diagnostic tests may be used to identify pelvic venous thrombosis. Ultrasound examination is often the first test performed. This test uses sound waves to create images of the veins and can help identify enlarged veins and blood clots^[5][7]. Ultrasound is a quick, inexpensive, and safe test that does not expose patients to radiation^[7].

Computed tomography, commonly called a CT scan, is another imaging test that can help diagnose pelvic venous thrombosis^[2][5][7]. A CT scan uses X-rays and a computer to create detailed cross-sectional images of the body. When performed with contrast dye injected into a vein, CT scanning can clearly show blood clots in the pelvic veins^[7].

Magnetic resonance imaging, or MRI, uses magnets and radio waves to create detailed images of the body’s soft tissues^[5][7]. MRI can help visualize abnormal veins within the pelvis and evaluate surrounding structures^[7].

Venography, also called a venogram, is considered the most definitive imaging test for diagnosing pelvic venous thrombosis^[5][7]. During this procedure, a thin tube called a catheter is inserted into the blood vessel system, usually from the groin or neck. X-rays are then used to guide the catheter into the pelvic veins, and a special dye is injected. Images are taken to look for blood clots or other abnormalities. A positive finding on venography is the presence of a filling defect that is consistent with a clot within the vein^[7].

Treatment Options

Treatment for pelvic venous thrombosis aims to prevent the clot from getting larger, stop new clots from forming, and reduce the risk of the clot breaking loose and traveling to the lungs^[2][5].

The main treatment for pelvic venous thrombosis is medication to prevent blood clotting. These medications, called anticoagulants or blood thinners, make it harder for blood to clot^[2][3]. Anticoagulants can stop clots from getting bigger and may also prevent new clots from forming. However, they do not break up existing clots. The body’s natural systems work to dissolve the clots over time^[2].

When pelvic venous thrombosis occurs after childbirth or is associated with infection, treatment typically includes both antibiotics to fight infection and anticoagulation therapy^[7].

In some cases, doctors may recommend minimally invasive procedures to treat pelvic venous thrombosis. These procedures may involve using a balloon to widen a narrowed area of the vein and placing a small tube called a stent to keep the affected area open^[2][5]. In cases where veins are leaking blood backward, abnormal veins can be sealed shut with small coils or glue to relieve symptoms^[5].

Some patients with pelvic venous thrombosis may need to wear compression stockings. These specially designed garments help improve blood flow in the legs and can reduce swelling^[2].