An HSG, or hysterosalpingogram, is an X-ray test that checks whether your fallopian tubes are open and whether the inside of your uterus looks normal. It’s one of the most common diagnostic tests in a fertility workup, typically ordered when you’ve been trying to conceive without success. A special dye is injected through your cervix, fills your uterus, and travels through your fallopian tubes while X-ray images capture the path in real time.
Why an HSG Is Ordered
The primary reason for an HSG is to find out if your fallopian tubes are blocked. Blocked tubes prevent an egg from meeting sperm, and tubal problems account for a significant portion of female infertility. The test can reveal whether a blockage is partial or complete, and whether it affects one or both tubes.
Beyond tubal evaluation, the dye filling your uterus creates an outline of the uterine cavity on X-ray. This can reveal structural issues like polyps, fibroids pushing into the cavity, scar tissue (adhesions), or an unusually shaped uterus. These findings can explain difficulty conceiving or recurrent pregnancy loss. An HSG is also sometimes used to confirm that a tubal sterilization procedure was successful.
How the Procedure Works
The entire test takes about 15 to 30 minutes and is done in a radiology suite, not an operating room. You lie on an exam table, and a speculum is placed just like during a Pap smear. A thin catheter is then threaded through your cervix into the uterus. Through this catheter, a contrast dye (visible on X-ray) is slowly injected, usually starting with just 1 to 3 mL.
As the dye fills your uterine cavity, the radiologist takes a series of X-ray images. If your tubes are open, the dye flows through them and spills out the ends into your pelvic cavity. That spillage is actually what the doctor wants to see. It confirms the tubes are “patent,” meaning clear and unobstructed. If the dye stops at any point along a tube and doesn’t spill, that tube may be blocked.
When to Schedule It
Timing matters. The test is scheduled 7 to 10 days after the first day of your last period. This window falls after your period has ended but before ovulation, which serves two purposes: the uterine lining is thin enough for a clear image, and there’s virtually no chance you could be pregnant during the test. Pregnancy is a key reason the test would be postponed. Active pelvic infection and an allergy to iodine-based contrast dye are also reasons the procedure shouldn’t be done.
What It Feels Like
This is the question most people actually want answered. The honest range of experiences is wide. Many women describe cramping similar to period pain, along with a feeling of pressure or fullness in the lower abdomen as the dye enters the uterus. For some, the discomfort is mild and brief. For others, it’s more intense, particularly if a tube is blocked (because the dye creates more pressure against the obstruction). Nausea and lightheadedness can occasionally occur.
The cramping typically eases quickly once the procedure is over, and most people feel back to normal after resting for about an hour. You’ll likely be asked to stay for observation during that time. Light spotting and mild cramping can continue for a day or two afterward. Many providers recommend taking an over-the-counter pain reliever about an hour before the appointment to help with discomfort.
What the Results Mean
Results are often available the same day. The key findings fall into a few categories:
- Open (patent) tubes: The dye flows freely through both tubes and spills into the pelvic cavity. This is a normal result.
- Blocked tubes: The dye stops partway through one or both tubes. Blockages can be caused by scar tissue from past infections, endometriosis, or conditions like hydrosalpinx (a tube swollen with fluid).
- Pseudo-blockage: Sometimes a tube appears blocked due to temporary spasm or a mucus plug rather than actual structural damage. Your doctor may recommend repeating the test or using a different method to confirm.
- Uterine abnormalities: Irregularities in the shape of the dye-filled uterus can reveal polyps, fibroids, adhesions, or a septum (a wall of tissue dividing the cavity).
One important caveat: an HSG shows the inside of the tubes and uterus, but it can’t detect problems on the outside, like endometriosis on the surface of the ovaries or tubes. Other tests, such as laparoscopy, are needed for that.
The Unexpected Fertility Boost
One of the more surprising things about an HSG is that the procedure itself may improve your chances of getting pregnant in the months that follow. The flushing action of the dye appears to clear minor debris or mucus from the tubes. Research from a large trial published in the New England Journal of Medicine found that the type of dye used makes a difference. Women who had their HSG with oil-based contrast had a 39.7% ongoing pregnancy rate in the six months afterward, compared to 29.1% for those who received water-based contrast. Live birth rates followed a similar pattern: 38.8% versus 28.1%. This “therapeutic flushing” effect is significant enough that some fertility specialists consider the test partly a treatment, not just a diagnostic step.
Risks
The HSG is a low-risk procedure overall. Pelvic infection is the most notable concern, occurring in fewer than 1 to 3 out of every 100 patients. The risk is higher if you have a history of pelvic inflammatory disease or an existing tubal condition, and some providers prescribe a short course of antibiotics beforehand as a precaution. Allergic reactions to the contrast dye are rare. The radiation exposure from the X-rays is minimal and focused on the pelvis.
Cost
If you’re paying out of pocket, an HSG typically costs in the range of $400 to over $1,000 depending on where you live and the facility. Bundled pricing through platforms like MDsave lists the test around $393 in some states, which includes facility and radiology fees. Many insurance plans cover the HSG as part of a fertility evaluation, but coverage varies widely, so checking with your insurer beforehand is worth the call.