A small amount of fluid is injected into the uterus while X-ray pictures are taken of the pelvis.
The HSG will identify any abnormalities on the inside of the uterine cavity, and can determine whether the Fallopian tubes are open, blocked, or otherwise abnormal. The fluid should continue from the uterus into each Fallopian tube (the tube on the left side is blocked in the picture). If both tubes are blocked the sperm can not reach the egg and fertilization can not take place.
For more information, see the American Society of Reproductive Medicine (ASRM) patient Fact Sheet Hysterosalpingogram (HSG).
