The Doctor Recommended Guide to Understanding May-Thurner Syndrome - Symptoms and Treatment

What is May-Thurner Syndrome?

May-Thurner Syndrome (MTS), sometimes called Iliac Vein Compression Syndrome, primarily affects women between the ages of 20 and 45. Women diagnosed with MTS will have compression of the left iliac vein leading to a decrease in drainage of the left leg. If left untreated, this may lead to the formation of a deep vein thrombosis (blood clot).

The Deep Vein Thrombosis (DVT) can restrict blood flow causing pain, swelling and sometimes varicose veins in the left leg. May-Thurner Syndrome presents on the left side, though cases where there are right sided symptoms have been reported.

May-Thurner Syndrome

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Population and demographics

May-Thurner Syndrome primarily affects women between ages 20 and 45. Common symptoms include generalized pelvic pain, painful leg swelling and varicose veins (usually affecting the left leg.)

The disorder is prevalent after prolonged immobilization or pregnancy. Patients may also present with stigmata associated with post-thrombotic syndrome such as pigmentation changes, varicose veins, chronic leg pain, phlebitis and recurrent skin ulcers.

Symptoms and Causes of the disease

May-Thurner Syndrome (MTS) occurs when the right common iliac artery compresses the left common iliac vein, restricting the drainage of blood from the lower extremities. MTS is most common in women who have been pregnant and rarely occurs in women who have not had children. MTS can also occur in men though it is less likely. When left untreated, May-Thurner Syndrome may progress through three stages:

Stage 1: Iliac vein compression - symptoms may or may not be present.

Stage 2: Venous spur formation - fibrous shelves that develop in the vein, restricting blood flow and increasing disposition for deep vein thrombosis (DVT).

Stage 3: Deep vein thrombosis (DVT) - formation of a clot in the vein. Blood flow is severely restricted, leading to pain and swelling in the legs and the formation of varicose veins.

Center for Vascular Medicine is one of the leading out-patient based practices in the nation for the treatment of venous conditions in the pelvic region which cause pelvic pain.

Patients with mild narrowing of the vein will often experience no symptoms. As May-Thurner progresses, the following symptoms are common:

  • Generalized pain in the lower abdomen and pelvis
  • Varicose veins in the upper leg (usually left leg)
  • Swelling in the leg (usually left leg)
  • Chronic pain in the legs that worsens as the day goes on
  • Chronic Hemorrhoids

May-Thurner Syndrome Diagnosis

Patients generally come to Center for Vascular Medicine for the diagnosis of May-Thurner Syndrome after experiencing symptoms for several months to years. Oftentimes, they are referred by their OB/GYN or primary care physician. If left untreated, MTS may develop into a Deep Vein Thrombosis (blood clot). We use a number of non-invasive and minimally invasive tests in the outpatient setting. These may include:

May-Thurner Treatment

Treatment for MTS varies based on the patient’s specific condition. At Center for Vascular Medicine, we strive to provide the most conservative treatments that will deliver long lasting relief. Most treatments are minimally invasive and are performed in the outpatient setting.

A majority of women diagnosed with May-Thurner Syndrome will undergo a minimally invasive procedure to place a stent in the compressed iliac vein. Using a combination of intravascular ultrasound (IVUS) and venography, the physician will precisely determine which vein segments are diseased and to what extent. Based on the length and severity of the diseased vessel, a balloon and stent may be deployed into the vein to restore blood flow.


Venoplasty refers to a technique used to open blocked veins by inflation of a balloon catheter. This technique is typically used in conjunction with stenting although not always. The balloon is removed after it is used.

Iliac Vein Stenting

A stent is used to open a vessel and improve blood flow. The vascular specialist will insert a cylindrical metal wire mesh tube into the artery in order to keep the blood flow channel open.

May-Thurner Syndrome Prevention

While measures may be taken to reduce the risk of developing May-Thurner Syndrome, it may not be completely avoided.  Some ways of reducing the risk of developing May-Thurner may include the following:

  • Use of pantyhose style compression devices throughout pregnancies.
  • Use of compression stockings/socks on a routine basis during times of prolonged standing or sitting and with traveling long distances
  • Maintain a healthy BMI/weight .
  • Maintain a healthy weight gain during pregnancies.
  • Routine exercise that uses the calf muscles to promote blood flow out of the veins.

May-Thurner Syndrome Progression

Symptoms of May-Thurner Syndrome typically begin as mild which are worse in the left leg.  Symptoms can include achiness, heaviness, fatigue and swelling in the leg.  These symptoms may or may not be associated with visible varicose veins.  Pelvic pain, groin pain, and lower back pain, more noticeable on the left side may also be present.

Without treatment, May-Thurner Syndrome can progress and cause long-term symptoms difficulties and disabilities. Untreated May-Thurner Syndrome increases risk of deep vein thrombosis (DVT), however, It’s worth noting that DVT is not always a result of or present with May-Thurner Syndrome. 

If a patient has been evaluated with the above symptoms, the physician should consider the possibility of May-Thurner Syndrome and order non-invasive imaging such as:

  • CT Scan or MRI
  • Doppler sonogram

Stage 1 of May Thurner Syndrome is when compression of the vein is identified however the patient may be asymptomatic or present with only mild symptoms. If symptoms are mild, the physician may order compression stockings, also known as “support hose.” Compression stockings apply pressure to your lower legs to help maintain blood flow while reducing swelling and other related symptoms.

May-Thurner Syndrome may progress to Stage 2, venous spur formation, while the patient still remains asymptomatic. As this increases DVT’s likelihood, it becomes more urgent to improve blood flow in the left iliac vein. This treatment may involve more invasive procedures, such as bypass surgery, angioplasty, stenting, or the right iliac artery’s repositioning.

If May-Thurner Syndrome progresses to Stage 3, which is DVT, the patient will require aggressive treatment. In addition to the procedures as mentioned earlier, your physician may prescribe one, or more, of the following:

  • Blood thinners
  • Clot busters
  • Vena cava filter

Left untreated, DVT could result in a blood clot traveling through the bloodstream and becoming stuck, cutting off the lungs’ blood supply and causing a pulmonary embolism.

At this point, the patient may have chest pain, cough up blood, accelerated heartbeat, and breathing problems. As DVT may be fatal, it is vitally important that the patient seek medical treatment immediately.

Therefore, as May-Thurner Syndrome is a progressive disease, early diagnosis and treatment are essential for better long-term outcomes.

This article is a comprehensive overview of May-Thurner Syndrome. However, it should not take the place of speaking with a physician. If you are experiencing any of the symptoms listed above, or know someone who is, contact our vascular surgeon in Silver Spring Maryland today to schedule a consultation.

You can also view other vascular diseases below:

Pelvic Congestion Syndrome

Deep Vein Thrombosis

Peripheral Arterial Disease (PAD)

Chronic Venous Insufficiency

Post-Thrombotic Syndrome


While there is no “cure” for May-Thurner Syndrome, it can be treated successfully to relieve symptoms. Most procedures are minimally invasive. With treatment, the patient can soon engage in their normal daily activities. However, regular follow-ups with a physician will be necessary. Although it is in a small percentage of patients, additional procedures may need to be done to treat additional areas of compression.

Some patients have reported fatigue, along with other symptoms, such as varicose veins and leg ulcers. If you feel exhaustion, accompanied by heaviness and swelling in your leg, it is vital to seek medical treatment immediately.

Patients with May-Thurner Syndrome may have persistent low back pain. The iliac vein’s narrowing will cause some patients to experience pain in their lower back, along with pelvic pain, bladder and bowel problems, bloating, and hemorrhoids. It is difficult to determine how much back pain is due to the iliac vein compression or other possible chronic back problems.

Dr. Sanjiv Lakhanpal

Dr. Sanjiv Lakhanpal

Dr. Sanjiv Lakhanpal published in several medical research journals through the Lakhanpal Vein Foundation to help educate and raise awareness for vascular disease. He has been practicing medicine for 25 years, and is the founder of The Center for Vascular Medicine.