Uncomfortable and expensive tests sometimes done before surgery to treat the most common cause of urine leakage in women may be unnecessary, according to a new study involving 630 volunteers at 11 medical centers.

Researchers found no difference in the success rate of urinary incontinence surgery for patients that received the testing and women who were simply screened for leakage in their doctor's office.

Doctors "need to do a careful history and exam, and if you do that you probably don't need an expensive, uncomfortable and invasive test," lead researcher Dr. Charles Nager of the University of California, San Diego, told Reuters Health.

About 260,000 women have surgery each year for stress urinary incontinence -- urine leakage that can be triggered by coughing, sneezing or other physical movement. That type of incontinence affects up to half of U.S. women at some point in their lives.