HSG (hysterosalpingogram)
An HSG is an X-ray test that checks whether your fallopian tubes are open and whether the shape of your uterus looks normal. It is one of the first tests done when investigating infertility, because a blocked tube is a treatable cause. The procedure itself can cause mild to moderate cramping for a few minutes, and some evidence suggests it can slightly raise the chance of pregnancy in the months after, especially with an oil-based dye.
An HSG (hysterosalpingogram) is an X-ray of the uterus and fallopian tubes. A thin catheter passes a small amount of dye through the cervix, and the X-ray shows whether the dye flows freely through the tubes, which suggests they are open, and whether the shape of the uterine cavity looks normal. Blocked tubes stop an egg and sperm from meeting, so this is one of the first tests ordered when investigating infertility.
When it is done
An HSG is usually done in the first half of the cycle, after a period ends and before ovulation, so there is no chance of disturbing an early pregnancy. It takes about 10 to 15 minutes and is normally done as an outpatient procedure, without sedation.
What the result can tell you
If the dye spreads freely into the pelvis on both sides, the tubes are read as open. If it stops partway or does not spill on one or both sides, that suggests a blockage, which might be at one end of the tube or along its length. The test also shows the general shape of the uterine cavity, including some structural findings like a septum or a large fibroid distorting the cavity. It does not show endometriosis or assess ovarian reserve.
A test that may also help
Beyond diagnosis, several trials have found a modest treatment effect from the procedure itself, particularly when an oil-based (rather than water-based) dye is used. One large trial found pregnancy rates rose from around 29% to around 39% over the following months when an oil-based dye was used instead of no additional flushing. The likely explanation is that the flush clears debris or mucus from tubes that are open but partly obstructed. Ask your clinic which type of dye they use and whether it fits your situation.
Next steps
A confirmed blockage does not rule out a pregnancy. Depending on where the blockage is and what else is going on, options range from surgery to open a tube, to skipping straight to IVF, which bypasses the tubes entirely. Our guide on when to seek help covers how this test usually fits into a first work-up.
Related
Last updated .