(NEXSTAR) – Colorado Republican Rep. Lauren Boebert went to the hospital this week when she noticed “extreme swelling” in her leg. Doctors ran some tests, and diagnosed Boebert with May-Thurner syndrome, her campaign said.

The little-known syndrome occurs when the right iliac artery, located in the abdomen, presses onto the left iliac vein, which is responsible for blood flow between the left leg and heart, explains Cleveland Clinic. That pressure can interrupt blood flow to the legs.

If blood can’t get back to the heart, it may start to pool in the legs and create a blood clot, or deep vein thrombosis.

Boebert saw signs of a problem because there was “severe swelling in her upper left leg,” her campaign said.

The syndrome usually impacts the left leg. Other symptoms include heaviness, pain, skin discoloration, swelling or sores on the left leg.

While the name of May-Thurner syndrome isn’t commonly known, the problem isn’t exactly rare. A 2012 medical journal publication estimated 1 in 5 people experience this type of vein compression, but many are not diagnosed. It can go unnoticed unless a person experiences blood clots.

The syndrome is more common in women, and in adults between 20 and 50 years old, Cleveland Clinic says.

Boebert, 37, was treated with a surgery to remove the clot, her campaign said. A stent was also put in place to aid normal blood flow.

“After taking time to rest as recommended by doctors, she is expected to make a full recovery with no significant concerns for her long-term health and no hindrance to her ability to perform her duties as a Congresswoman,” the campaign statement reads.

The far-right Congresswoman currently represents Colorado’s 3rd district as she runs for the 4th district seat on the other side of the state.