What Is an HSG Test?

A hysterosalpingogram (HSG) is a special kind of x-ray used to evaluate female fertility. It is an outpatient procedure that takes no longer than a half-hour. And HSG test involves placing an iodine-based dye through the cervix and taking x-rays. These x-rays help evaluate the shape of the uterus and whether the fallopian tubes are blocked.

Many patients wonder if the test will cause pain. The answer varies from person to person. Some people report mild to moderate cramping. Some don't feel anything unpleasant during the test. Very few report severe cramping. Many say afterward that their fear of pain was much worse than any discomfort they felt. Additionally, various pain medications can be used, as needed, to make the procedure more comfortable.

Before the HSG Test

An HSG should be done after your period but before ovulation. This is to reduce the risk of having the test when you're pregnant. Your fertility clinic or doctor will advise you to call the radiology facility on day 1 of your period to schedule the test.

The HSG is performed while you are awake and does not involve general anesthesia. You won't need to fast the day or night before. Some doctors prescribe antibiotics to reduce the risk of infection.

HSG Test Step-by-Step

You’ll lie down on a table, usually with stirrups. If they don't have stirrups, you might need to lie on the table, bend at your knees, with your feet (sort of) flat on the table, and hold your legs apart.

Pelvic Exam

The doctor will perform a quick pelvic exam. The technician, nurse, or doctor will insert a speculum into your vagina. This is the same metal device used during your yearly gynecological exam.

If you experience pain during your annual visit, then this may be painful for you. Women who suffer from sexual pain may also experience pain during gynecological exams.

X-Ray Prep

An x-ray machine will be lowered over your abdomen. This can feel a bit awkward, especially with the speculum and your knees up. Next, they will insert a swab to clean off the cervix. This is to reduce the risk of infection. If your cervix is sensitive to touch, this may be a bit achy, but most women don’t experience pain from this.

Next, they will insert a plastic catheter called a cannula into the cervical opening. This feels kind of like a pap smear and might be a little uncomfortable. Or, you may not feel anything.

Dye Injection

Finally, an iodine-based dye will be injected through the catheter. When the dye is injected, you may feel a warming sensation. This dye will go through your uterus, through the fallopian tubes (if they are open), and spill out into the pelvic cavity.

X-Rays Taken

After injecting the dye, your doctor will take the x-rays. For each x-ray picture, you'll be asked to hold your breath for a moment or two. You may be asked to change your position. For example, you may be asked to lie on your side. You may feel uncomfortable with the speculum inside and the x-ray over you. Your doctor understands. Ask for help if you need it.

Once the doctor has decided that the pictures are satisfactory, the x-ray machine will be lifted up and the speculum removed. You're free to go home.

Managing HSG Test Discomfort

The test can be nerve-wracking, with this big x-ray machine hovering over you while you're lying on your back, legs apart, with the speculum inside. The nurse or doctor may ask you to roll over to your side for an x-ray or two, and you have to do it with the speculum still between your legs.

In most pregnant people, the dye painlessly passes through the uterus, through the fallopian tubes, and out into the abdominal cavity. However, if your tubes are blocked, the dye can cause pressure, causing substantial discomfort. If you do feel intense pain, tell your doctor right away. They can quickly remove the catheter, which will release the pressure and should eliminate your pain.

On the day of the test, your doctor may suggest taking a painkiller like ibuprofen an hour before your HSG is scheduled, or you may decide to take it afterwards. This can help with the discomfort of the test. Most doctors recommend taking ibuprofen an hour before the HSG. This can reduce mild cramping during the test. Anxiety and fear about the test can increase your perception of pain.

After the Test

You may experience mild cramps and light spotting. Over-the-counter pain relievers should help with cramps. You'll be able to resume regular activity after the test. Some doctors may tell you to refrain from sexual intercourse for a few days after the test.

There is a rare risk of infection following an HSG. Increasing pain may hint that an infection is developing.

What HSG Test Results Mean

After your test, your provider will deliver your test results. The HSG helps the doctor check out two important factors:

Are the Fallopian Tubes Open?

If the fallopian tubes are blocked, the egg can't meet the sperm and conception is not possible. There are several potential causes and corresponding treatments if this is the case.

Are There Any Uterine Abnormalities?

In some women with recurrent pregnancy loss, an abnormally shaped uterus is to blame. An HSG test can also show fibroids or polyps that could get in the way of an embryo implanting and/or growing. Some uterine abnormalities can be treated with surgery. 

Normal Results

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. This doesn't, however, mean your fertility is normal. It just means whatever may be wrong wasn't seen on the HSG.

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. (Hysteroscopy involves placing a thin, telescope-like camera through the cervix to look at the inside of the uterus.) 

Also, endometriosis can't be diagnosed with an HSG. Only an exploratory laparoscopy can rule out or diagnose endometriosis.

Abnormal Results

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." This is when 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.

HSG Test Risks and Safety Concerns

An HSG is a generally safe procedure. Still, there are some safety concerns and potential risks of an HSG test.

Potential Risks

Infection may occur in less than 1% of cases. This is more common if you've already had an infection or you're at risk for pelvic inflammatory disease (PID). If you experience fever or increasing pain after the test, call your doctor. If you have a history of PID, sexually transmitted infection, or abdominal surgery (such as an appendectomy), your doctor may prescribe antibiotics for the procedure as an extra precaution.

Another risk is fainting during or after the test. If you feel dizzy after the exam, tell your doctor. It may be better for you to remain lying down until you feel less woozy.

A rare but potentially serious risk is iodine allergy. If you are allergic to iodine or shellfish, tell your doctor before the test. If you have any itching or swelling after the test, tell your doctor.

Safety Concerns

Usually, when you have an x-ray, the first thing the technician does is cover your pelvic area. During an HSG, the x-ray is aimed right at the pelvis. Be reassured that an HSG involves a very low amount of radiation. It has not been found to cause any unwanted effects, even if you get pregnant later that cycle.

However, an HSG should not be done during pregnancy. If you think you may be pregnant, tell your doctor before you have the test.

A Word From Verywell

It's understandable to feel nervous before and during an HSG exam. Deep, relaxed breathing through the procedure can help. Also, don't be afraid to tell the nurse or doctor that you're nervous or in pain. The nurse may even offer to hold your hand, which really can help you feel better.

Overall, the procedure is quick, and for some, it's completely painless. If you do feel pain, in most cases, it's short-lived and light. Alert your doctor if this isn't the case, and they will take quick steps to relieve pressure and pain as quickly as possible. Before your exam, also ask if your doctor recommends taking a painkiller.