Unintentional loss of urine due to physical movement or activity such as coughing sneezing, heavy lifting, exercise, laughing and standing up. Symptoms may not be experienced at all times, but may worsen with a full bladder. USI is caused by poor function of the muscles that support the bladder relaxation and contraction. Factors that increase the risk of developing USI are age, obesity, previous pelvis surgery, multiple pregnancies and forceps delivery.