Mary Anne Huntsman, 22, was admitted to the University of Utah Medical Center over the weekend after complaining of chest pains for a few days, said Huntsman's spokeswoman Lisa Roskelley.

Doctors are not sure of the cause. She is being treated with blood-thinning medication and is expected to remain hospitalized until Thursday, Roskelley said.

"This is just one of those strange things," said Roskelley. "They're just really glad they caught it early on and were able to treat it."

A pulmonary embolism is a blood clot that usually forms in the large veins in the legs, breaks loose and travels to the lungs.

Smaller clots don't pose a serious problem, but a major clot could be more serious, putting a strain on the lungs, and could potentially be fatal, said Dr. Richard Kanner, a pulmonary specialist at the University of Utah Medical School.

He said that the anti-coagulant keeps the clot from growing and the clot is generally absorbed by the body. There are a number of factors, including heredity, that can predispose a patient to an embolism. The clots commonly form after long periods of inactivity or after surgery.

Mary Anne Huntsman is a student at the Manhattan School of Music, but was home for the summer.

The governor was scheduled to be in Nevada today for a fundraiser for Sen. John McCain's presidential campaign, but canceled the trip.

Last month, the governor's son, Jon Huntsman III, broke a leg in a motorcycle crash.