Saline Infused Sonohysterogram is a procedure to evaluate the shape of the endometrial/uterine cavity. SIS uses ultrasound and sterile fluid to detect any abnormalities within the uterine cavity. Typically this test is performed 7-10 days after the start of your period. We begin by evaluating the uterus and ovaries using a vaginal transducer. Next, your physician places a speculum into the vagina and a small catheter is placed through the cervical os, into the endometrium. Once the catheter is in place, the speculum is removed and the vaginal transducer is once again placed in the vagina. This allows your physician to visualize the cavity while the sterile saline fills and outlines the cavity.