Hysteroscopy is used to diagnose or treat problems of the uterus. A hysteroscope is a thin, lighted telescope-like device. It is inserted through your vagina into uterus. The hysteroscope transmits the image of your uterus onto a screen. Other instruments are used along with the hysteroscope for treatment. A speculum is first inserted into the vagina. The hysteroscope is then inserted and gently moved through the cervix into your uterus. Carbon dioxide gas or a fluid, such as saline (salt water), will be put through the hysteroscope into your uterus to expand it. The gas or fluid helps your health care provider see the lining more clearly. The amount of fluid used is carefully checked throughout the procedure. Your health care provider can view the lining of your uterus and the openings of the fallopian tubes by looking through the hysteroscope. If a biopsy or other procedure is done, small instruments will be passed through the hysteroscope.