What is an HSG (Hysterosalpingogram)?
A hysterosalpingogram (HSG) is a special kind of x-ray. Hysterosalpingogram is pronounced /he-ster-o-sal-ping-o-gram/, but luckily, almost no one calls it by the full name. They just say HSG.
An HSG is an outpatient procedure, which takes no longer than a half hour. It involves placing an iodine-based dye through the cervix and taking x-rays to help evaluate the shape of the uterus and whether or not the fallopian tubes are open or blocked.
When is an HSG Ordered?
An HSG may be ordered as part of an infertility work-up. It's also commonly ordered if a woman has experienced two or more miscarriages, since abnormal uterine shape can cause recurrent pregnancy loss.
Why is the HSG Test Important?
The HSG helps the doctor check out two important factors:
Whether or not the fallopian tubes are blocked or open.
If the fallopian tubes are blocked, a woman will not be able to get pregnant, because the egg can't meet the sperm. You can read more about diagnosis, causes, and treatment for blocked fallopian tubes here:
Whether or not the shape of the uterus is normal.
In 10% to 15% of women with recurrent pregnancy loss, an abnormally shaped uterus is to blame. Some uterine abnormalities can be treated with surgery. You can read more about the connection between uterine shape and miscarriage here:
How Do You Prepare for an HSG?
An HSG is usually preformed after your period, but before ovulation. This way it won't interfere with a pregnancy. This commonly falls out between day 10 and 12 of your menstrual cycle. Talk to your fertility clinic about scheduling the HSG, which might be tricky if you have irregular periods.
The HSG is performed while you are awake and does not involve general anesthesia, so you won't need to fast the day or night before. Your doctor may suggest taking a pain killer like ibuprofen an hour before your HSG is scheduled. This can help with the discomfort of the test. Also, some doctors prescribe antibiotics, to guard against infection.
How is an HSG Done?
For the test, you'll lie on an examination table, usually one with stir-ups like the ones found in a gynecologist's office. The doctor will perform a quick pelvic exam, and place a speculum inside your vagina. Then, the doctor will place a device called a cannula into your cervix.
Next, the doctor will inject an iodine-based dye through the cannula. After the dye has been injected, the doctor will lower an x-ray device over your pelvic and lower abdominal area. For each x-ray picture, you'll be asked to hold your breath for a moment or two. You may need to change your position, and lie on your side, for some of the x-rays.
In some women, the test may cause some cramping.
Once the doctor has decided that the pictures are satisfactory, the x-ray machine will be lifted up, the speculum removed, and you're free to go home.
What are the Risks of an HSG?
Generally, an HSG is considered to be a safe procedure. Still, there are potential risks.
In less than 1% of cases, infection may occur. This is more common if there has been previous infection of the fallopian tubes. If you experience fever or increasing pain after the test, you should call your doctor.
Other potential risks include fainting during or after the test and iodine allergy (rare). If you are allergic to iodine or shellfish, tell your doctor before the test. If you have any itching or swelling after the test, talk to your doctor.
Is the Radiation from an HSG Safe?
An HSG involves a very low amount of radiation. The low amount does not seem to causes any unwanted effects, even if you get pregnant later that cycle.
However, an HSG should not be done during pregnancy.
How Will I Feel After the Test?
You may experience mild cramps and light spotting. Over-the-counter pain relievers should help with cramps. (See this article on HSG and pain for more information.)
Generally, you'll be able to resume normal activity after the test. Some doctors may tell you to refrain from sexual intercourse for a few days after the test.
What Do the Results Mean?
If the x-ray shows a normal uterine shape, and the injected dye spills freely out from the ends of the fallopian tube, then the test results are considered normal. Tubal factor infertility or abnormal uterine shape is probably not the cause for your infertility.
However, if further testing does not reveal a cause for the infertility or recurrent pregnancy loss, your doctor may order a hysteroscopy to double check the findings of the HSG, specifically to recheck for problems with the uterus. (Hysteroscopy involves placing a thin, telescope like camera through the cervix, to look at the inside of the uterus.) One small study found a 35% incident of false negatives with an HSG. In other words, the HSG showed a normal uterine shape, but a hysteroscopy showed abnormalities.
Also, an HSG is not able to diagnosis or rule out endometriosis.
What Happens If Results Are Abnormal?
If the dye shows an abnormally shaped uterus, or if the dye does not flow freely from the fallopian tubes, there may be a problem. It's important to know that 15% of women have a "false positive," where the dye doesn't get past the uterus and into the tubes. The blockage appears to be right where the fallopian tube and uterus meet. If this happens, the doctor may repeat the test another time, or order a different test to confirm.
An HSG can show that the tubes are blocked, but it can't explain why. Your doctor may order further testing, including exploratory laparoscopy or a hysteroscopy, to investigate and possibly correct the problem.
You can read more about causes and treatment for blocked fallopian tubes and abnormal uterine shape in these articles:
- Blocked Fallopian Tubes
- Pelvic Inflammatory Disease
- Uterine Malformations That May Lead to Miscarriage
More about fertility testing and infertility:
- Quiz: Are You Experiencing Endometriosis Symptoms?
- Quiz: Do I Have PID Symptoms?
- Quiz: Is Your Period Normal?
- What to Expect During Fertility Testing
- How to Cope When Trying to Conceive Overwhelms You
- Symptoms and Risk Factors of Infertility
- Causes of Infertility
- Take a Fertility Quiz
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Hysterosalpingogram (HSG): Patient Fact Sheet. American Society of Reproductive Medicine. Accessed November 13, 2008. http://asrm.org/uploadedFiles/ASRM_Content/Resources/Patient_Resources/Fact_Sheets_and_Info_Booklets/hsg.pdf
Recurrent Pregnancy Loss: Patient Fact Sheet. American Society of Reproductive Medicine. Accessed November 13, 2008. http://asrm.org/uploadedFiles/ASRM_Content/Resources/Patient_Resources/Fact_Sheets_and_Info_Booklets/recurrent_preg_loss.pdf
Wang CW, Lee CL, Lai YM, Tsai CC, Chang MY, Soong YK. "Comparison of hysterosalpingography and hysteroscopy in female infertility." The Journal of the American Association of Gynecologic Laparoscopists. 1996 Aug; 3(4):581