Hysterosalpingogram (HSG) is a procedure in which an X-ray is used to look at the internal shape of the womb(uterus) and to show whether the fallopian tubes are blocked. It is commonly carried out in the investigation of infertility.
During the procedure, a speculum is inserted into the vagina to keep it open. The cervix is then cleansed with an antiseptic solution. A thin tube called a cannula is then placed in the cervix and a radio-opaque dye known as contrast material is gradually injected into the uterus. A series of X-rays, or fluoroscopy, is done to follow the dye, which appears white on X-ray, as it flows into the uterus and the tubes.
If there is an abnormality in the cavity of the womb such as a fibroid or septum, it will be shown in the x-ray images.
If the tube is blocked, the dye will stop flowing. If the tube is open, the dye will fill it gradually and spill into the pelvic cavity.
The procedure usually takes about 10-15 minutes to complete. It is usually done in the period after menses and before ovulation so that the chances of the patient being pregnant are low.
There may be abdominal cramps or discomfort during and after the procedure. A pain killer taken an hour before the procedure usually suffices. Slight vaginal bleeding or spotting for a few days is also common. After the procedure, a course of antibiotics is given to prevent pelvic infection.
HSG is relatively safe. Occasionally, there may be an allergic reaction to the dye. Pelvic infection and injury to the uterus are rare.
Although HSG is commonly used as a first-line diagnostic test for infertility, it has some limitations.
It only visualizes the interior of the uterus and the fallopian tubes. Abnormalities of the ovaries, the wall of the uterus, pelvic infection and menstrual backflow(endometriosis) may not be assessed by this imaging technique.
Studies have also shown that if an occlusion is detected in HSG, there is a 60% possibility that the tubes are actually patent. This apparent blockage is due to the spasm of the fallopian tubes from the pain experienced by the patient during the procedure.