Saline infusion transvaginal ultrasound is a procedure that allows your physician to visualize and evaluate the uterus, benign fibroid tumors and polyps using sound wave technology. As with a traditional transvaginal ultrasound, a sterile wand is introduced through the vagina for this procedure. The difference is that a small catheter device is also inserted to deliver sterile water to the uterine cavity and expand it for greater visibility. This allows previously undetectable polyps to be seen and provides more information on fibroids that may be protruding from the uterine wall. The procedure may cause slight cramping for some patients as well as a light discharge that may continue for up to a day or two. However, most patients do not have any discomfort afterwards and can resume their usual activities right away.