What is a hysterosalpingogram (HSG) test?

If you're having trouble getting pregnant, your doctor may recommend a hysterosalpingogram (HSG). The test is a quick and relatively painless procedure to scan your uterus for any problems and to make sure your fallopian tubes aren't blocked. Read on for more about why and how an HSG is performed, as well as what to expect afterwards. 

woman getting HSG results
Photo credit: / Lordn

What is a hysterosalpingogram (HSG)?

A hysterosalpingogram, or HSG, is a procedure that checks the uterus and fallopian tubes for any blockages. It might be recommended as part of a routine fertility evaluation. Or, your doctor  may suggest it if they're concerned that one of your fallopian tubes may be blocked, or if they suspect you have another uterine abnormality.

In general, HSGs can be used to determine whether there's anything internal that's preventing your egg from reaching the uterus after it leaves the ovary. The reasons for blockages may include prior surgery for fibroid removal, endometriosis, or certain sexually transmitted infections (STIs) like chlamydia or gonorrhea. HSGs can also find irregularities in the uterus, such as scar tissue or polyps that are preventing implantation of a fertilized egg.

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Why is an HSG test done?

If you're struggling with infertility, there may be a problem with the way your eggs travel from the ovaries through the reproductive tract to meet the sperm and then move to the uterus to grow in the lining. If your ob-gyn suspects there's an issue with your uterus or fallopian tubes, they'll recommend an HSG.

Hysterosalpingography is a specific fertility test that's designed to look inside the uterine cavity. The test involves an X-ray using contrast dye to determine whether or not the fluid can flow normally through your tubes.

How is an HSG test done?

HSGs are similar to other gynecological exams you've had in the past. The procedure is pretty quick – it takes just a few minutes and you can go home the same day.

To start, you'll lie on your back with your feet in stirrups. The doctor, who might be your gynecologist, a radiologist or a reproductive endocrinologist, will place a speculum into your vagina. Next, a thin tube is inserted, the speculum is removed and your uterine cavity is filled with a fluid known as contrast dye.

This dye highlights the shape of your uterus and fallopian tubes so that it can be read easily on an X-ray. An imaging machine called a fluoroscope will be above you to create an image that's projected on a monitor. If the X-ray shows fluid moving through your tubes and flowing out near your ovaries, you've got a clear tract. But if the dye is not able to travel through your tubes, then something (such as scar tissue) may be blocking your tubes.

How to prepare for an HSG

As long as you're not pregnant, aren't bleeding vaginally and you're not allergic to certain items like seafood, iodine or contrast dyes, then you're likely a good candidate for an HSG.

Make sure to talk with your provider beforehand if you have or could have a sexually transmitted infection (STI). If you do, this procedure could spread germs through your reproductive system, causing a major infection. If you do have an STI, certain antibiotics may be prescribed for a few days to lower the risk of it flaring up.

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For the clearest picture of your uterus, it's best not to have your period (or to be too close to the start of it) as both lingering menstrual blood and a thick uterine lining can make it difficult to see.

Your provider may suggest an over-the-counter pain reliever to take an hour before your HSG, and may give you an antibiotic to prevent infection. There could be some mild discomfort during the HSG. Try to line up a ride home afterward as the procedure can leave some women feeling dizzy or light-headed. You might also have some cramping that could interfere with your driving ability.

What to expect after an HSG

You can expect some cramping and vaginal discharge that may be tinged with blood as the remaining fluid from this procedure trickles out of your body. Wear a pad (not a tampon) to soak it up. You may also experience other side effects after undergoing an HSG such as dizziness, an upset stomach, and nausea.

As for the next steps, if your tubes are indeed blocked, you may need surgery to clear them. One common option is laparoscopy, which uses a camera inserted into a tiny incision in your belly button. Or a laparotomy may be recommended, which is a more traditional surgery that uses a larger cut in the stomach (both are done under anesthesia).

Signs of infection after HSG

Undergoing an HSG isn't risky. The amount of radiation is minimal and won't have any impact on any future pregnancies, even if you conceive the same month as the procedure. In fact, it's rare to have complications afterward (one might be injury to the uterus). That said, an infection can develop, especially if you have tubal scarring or an allergic reaction to the dye that's used. Signs of an allergy to dye include itching, swelling and a rash.

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Alert your doctor right away if you experience any of the following symptoms of infection:

  • Fever, chills
  • Fainting
  • Vomiting
  • Foul-smelling discharge
  • Heavy vaginal bleeding
  • Severe stomach pain or intense cramping

Can having an HSG improve my fertility?

Since infertility is due in large part to blocked fallopian tubes, having an HSG can, indirectly, lead to the help you need to eventually conceive. Undergoing an HSG can possibly clear small blockages and improve your chances of pregnancy. But results are decidedly mixed on this front.

One study analyzed the data from 13 trials involving almost 2,500 women and found that when an HSG was performed with an oil-soluble dye, the chance of pregnancy may go up. Still, the authors admit that the quality of evidence is low and HSG isn't currently considered a procedure that can treat infertility, but rather, an important first step in most fertility plans. Ultimately, if the blockage you have can't be cleared through surgery, you doctor may suggest in vitro fertilization or other fertility treatment.

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BabyCenter's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world. When creating and updating content, we rely on credible sources: respected health organizations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing. Learn more about our editorial and medical review policies.

Cleveland Clinic. 2022. Hysterosalpingogram. a new window [Accessed August 2022]

Mayo Clinic. 2021. Infertility. a new window [Accessed August 2022]

Mohiyiddeen L. 2015. Tubal flushing for subfertility. Cochrane Library. a new window [Accessed August 2022]

Jennifer Kelly Geddes

Jennifer Kelly Geddes is a New York City-based writer, editor, and fact-checker, and the mom of two teen girls. In her free time, Geddes can be found on her yoga mat, cross-country skiing, walking her rescue pup (a shepherd mix named Django), and spending time with her husband and daughters.