A saline infusion sonogram (SIS) may be recommended by your doctor for evaluation of the uterine cavity. This technique identifies fibroids or endometrial polyps which affect the shape of the uterine cavity. It may also identify scarring within the uterine cavity.
SIS procedures are performed in the first half of the menstrual cycle, within a week of cessation of menstrual flow. There must be no menstrual bleeding for this test to provide accurate and useful information. The test must be done prior to ovulation. For most patients, this means the SIS is performed between cycle days 7 and 11.
The SIS is simple and usually painless. A speculum exam is performed, the cervix is cleansed with betadine antiseptic and a small tube is placed within the cervical canal and up into the uterus. The speculum is then removed and a vaginal ultrasound is performed. A small amount of sterile saline (salt water) is gently instilled into the uterus while the uterus is viewed by ultrasound. The test takes about five minutes. Following the test, there will be a small amount of fluid drainage from the vagina.
There is a theoretical risk of intrauterine and/or tubal infection associated with SIS. This risk is so rare that an established frequency of this complication is unknown.