Uterus Evaluation: Hysterosalpingogram

The Hysterosalpingogram (HSG) is a procedure done with contrast dye injected through the cervix into the uterus while observing with fluoroscopy (moving X-rays).

This procedure is done in conjunction with radiology and will have to be scheduled for a Tuesday afternoon.

Procedure Description

Since X-rays normally pass through soft tissue, a contrast agent must be used to show the cavity of the uterus and the fallopian tubes. The contrast agent is often referred to as the "dye" though it is a clear liquid. Iodine is the active agent in the liquid that prevents the X-rays from reaching the film.

By blocking the X-rays, the film has areas that are not exposed and remain clear. The contrast agent, or dye, can be readily absorbed by tissues so the liquid that does not come out at the completion of the test will pass out in the urine within several hours.

The procedure itself involves placing a speculum into the vagina for visualization of the cervix. A cleaning solution is used to clean the cervix and vagina. An instrument is then used to grasp the cervix to allow traction. A pinch, like an injection, may be felt at this point but this usually passes very quickly.

Next, the cannula with a rubber stopper on the end is placed against the opening of the cervix. This plugs the opening of the cervix so that as the "dye" is injected it does not spill back into the vagina.

Now the speculum is removed and the patient is positioned correctly under the X-ray machine. A radiologist is present to perform fluoroscopy, or real-time X-ray images.

As the contrast is slowly injected into the uterus, the image of the uterine cavity and fallopian tubes becomes visible on the monitor. Patients and family members are encouraged to watch the monitor as the procedure is being done.

Once the contrast has been injected the radiologist will take a still X-ray that demonstrates the HSG findings. Ideally, the contrast will appear to spill out of the ends of the fallopian tubes.

Patients with blocked tubes will either have tubes that do not fill with contrast, or tubes that fill without spill. Often dilated tubes will be demonstrated if the obstruction is at the fimbriated end of the fallopian tube.

After the still X-ray has been completed the procedure is finished. Most patients are surprised at how quickly the actual procedure can be accomplished.

Risks

Cramping

The most common risk during an HSG procedure is cramping. As the contrast fills the uterus and fallopian tubes, there are muscles that are stretched. These muscles respond with reflexive contractions that cause cramping. Spasm of the tubes tends to be more uncomfortable than uterine cramps but lasts a shorter amount of time.

Not all patients experience cramping, but it is a good idea to premedicate with an anti-inflammatory medication such as Motrin 800 mg or Advil Extra Strength. Mild cramping may continue throughout the remainder of the day while more intense cramping usually subsides shortly after the procedure.

Spotting

Another common risk is spotting. The instrument used to hold the cervix may cause light spotting that tends to be self-limited. A pad is usually provided to protect clothing.

Dizziness and Nausea

A vagal response may be one of the most concerning reactions to someone who is not properly prepared. This reaction involves the activation of a nerve that normally controls things such as intestines, the stomach, pulse, and blood vessels.

By manipulating the uterus and cervix, the vagal response can be triggered. This can cause a hot flush followed by dizziness, nausea, and potentially a blackout. Sitting or lying down helps to counteract this phenomenon which usually passes within several minutes.

Knowing this is a possibility removes a large portion of fear that can accompany a vagal reaction.

Infection

Infection to the uterus and tubes is theoretically possible but rarely seen. Because the contrast is injected through the uterus and tubes, bacteria can enter the reproductive tract. The female tract is quite capable of warding off infection.

Because there is concern for a patient’s tubes in terms of infection and damage, patients are given prophylactic antibiotics. Following the procedure, any disproportionate pain, fever, or unusual symptoms should be reported.

Radiation Exposure

Early pregnancies could potentially be exposed to radiation. Early exposure will have no effects or result in miscarriage. There are not any known mutations that occur from radiation exposure at these levels in early pregnancy.

Patients tested prior to cycle day 21 are not likely to have a positive test even if they are pregnant. Since there are no "perfect" tests to completely exclude pregnancy, there will always be a small risk. We are unable to delay the procedures for a pregnancy test so such matters need to be completed prior to the scheduled HSG.

Allergies

Contrast allergies to iodine compounds are possible. Patients with a history of anaphylaxis are the most at risk group. Premedication can be used with mild allergies.

Please discuss this issue, as well as your concerns, with your physician at the time you are told you need to have this procedure performed, so as not to encounter the unpleasantness of having to have your HSG rescheduled on the day you show up to have it done.

Findings

The HSG can reveal a number of findings. Uterine filling defects may be caused by fibroids, polyps, or scar tissue within the uterus. Abnormal uterine contours can be seen with fibroids and uterine anomalies such as a septate uterus or bicornuate uterus.

Defects can also be appreciated within the fallopian tubes as well as dilation at the ends of the fallopian tube. Abnormal positioning of the fallopian tubes can suggest the presence of scar tissue outside the tubes.

One must cautiously interpret the findings on an HSG since what is seen is a two-dimensional image of three-dimensional anatomy.

Another finding subject to interpretation is the tube that does not fill. Sometimes there is a suspicion that the tube is obstructed when what may be occurring is spasm of the tube or a pressure differential favoring the leakage of dye out of the other tube.

If necessary, abnormal HSG findings are confirmed with laparoscopy or hysteroscopy.

Since the fluoroscopy and X-ray images are taken and developed immediately, the physician performing the HSG will usually be able to review the findings following the procedure. The actions taken with abnormal findings will be up to the physician ordering the examination. A report and a copy of the HSG films will be returned to the ordering physician for review.

Preparing for an Appointment

Schedule an HSG for the week immediately after your menses, ideally between cycle days five to 12. The HSG procedure will be performed by a physician who will also briefly review the results with you after the procedure.

It is recommended that you have had a small lunch and have taken 600 to 800mg of ibuprofen one hour before the procedure. If you cannot take ibuprofen, then 500mg of Tylenol would be helpful to reduce cramping during the procedure.