A hysterosalpingogram (HSG) is an X-ray of the uterus and fallopian tubes which allows visualization of the inside of the uterus and tubes. The picture will reveal any abnormalities of the uterus as well as tubal problems such as blockage and dilation if sterilization reversal is planned, the point at which the tubes are blocked can be seen. This helps to plan the reconstructive procedure.
If the tubes are not blocked by scar tissue or adhesions, the dye will flow into the abdominal cavity. This is a good sign but it does not guarantee that the tubes will function normally. It does give a rough estimate of the quality of the tubal structure and the status of the tubal lining. Some cases where the tubes appear to be blocked where they join the uterus, may in fact be normal. Often blockage at this location may be due to spasm of the opening from the uterus into the tube or from accumulated debris and mucus blocking the opening. This can be managed by passing a very thin catheter into the fallopian tube either at the time of hysterosalpingogram or during a hysteroscopic procedure.
A hysterosalpingogram may also indicate endometrial polyps, submucus fibroids, intrauterine adhesions (synechia), uterine and vaginal septa uterine cavity abnormalities, or the after-effect of genital tuberculosis. The hysterosalpingogram may or may not be able to detect pelvic adhesions, mild hydrosalpinx, small polyps, endometriosis, tubal phimosis (clubbing of the fimbria at the end of the tube), or immotility of the tube. Other tests, such as hysteroscopy, saline sonohysterography or laparoscopy may be necessary to accurately evaluate the uterus.
Although the purpose of the hysterosalpingogram is not therapeutic, sometimes forcing dye through the tube will dislodge any material which blocks it. A number of women have become pregnant following a hysterosalpingogram without further treatment.