Hysterosalpingogram – HSG
What is a hysterosalpingogram?
A hysterosalpingogram , or HSG is an important test of female fertility potential. The HSG test is a radiology procedure usually done in the radiology department of a hospital or outpatient radiology facility.
- Radiographic contrast (dye) is injected into the uterine cavity through the vagina and cervix
- The uterine cavity fills with dye and if the fallopian tubes are open, dye fills the tubes and spills into the abdominal cavity
This shows whether the fallopian tubes are open or blocked and whether a blockage is at the junction of the tube and uterus (proximal) or at the other end of the tube (distal).
- Successful treatment for tubal factor infertility is available
Normal hysterosalpingogram picture A smooth triangular uterine cavity and spill from both tubes The bones of the pelvis are seen on the x-ray around edges of image
HSG with blocked tubes
HSG showing a normal uterus and blocked tubes No “spill” of dye is seen at the ends of the tubes Both tubes are slightly dilated and fluid filled – hydrosalpinx This woman went on to have successful in vitro fertilization for her tubal infertility
What else can be seen by a hysterosalpingogram, besides whether the tubes are open?
Other things that can be seen on a hysterosalpingogram include:
- The uterine cavity is evaluated for the presence of congenital uterine anomalies, polyps,fibroid tumors or uterine scar tissue
- The fallopian tubes are also examined for defects within them, for suggestion of partial blockage, and for evidence of pelvic scar tissue in the abdominal cavity near the tube
How do I prepare for the test?
Tell your doctor if you have ever had an allergic reaction to x-ray dye or if you have had a recent infection in the pelvis. Definitely tell your doctor if there is a chance you might be pregnant. If you have regular periods, it is best to have this test done in the week right after your period ends. This is before ovulation occurs in your cycle, so there would be the least risk of exposing an early pregnancy to the dye used in this test. Some doctors will require you to have tests for pelvic infections before having a hysterosalpingogram.
Some doctors recommend that you take antibiotics before the test. If this is your doctor’s practice, he or she will give you a prescription for this medicine.
You will need to sign a consent form giving your doctor permission to perform this test.
What to expect during a hysterosalpingogram
The hysterosalpingogram study only takes about 5 minutes to perform. However, the test is usually done in the radiology department of a hospital so there is additional time for the woman to register at the facility and fill out a questionnaire and answer questions regarding allergies to medication etc. The way the test is done is the following:
- The woman lies on the table on her back and brings her feet up into a “frog leg” position.
- The doctor places a speculum in the vagina and visualizes the cervix.
- Either a soft, thin catheter is placed through the cervical opening into the uterine cavity or an instrument called a tenaculum is placed on the cervix and then a narrow metal cannula is inserted through the cervical opening.
- Contrast is slowly injected through the cannula or catheter into the uterine cavity. An x-ray picture is taken as the uterine cavity is filling and then additional contrast is injected so that the tubes should fill and begin to spill into the abdominal cavity. More x-ray pictures are taken as this “fill and spill” occurs.
- When both tubes spill dye, the woman is often asked to roll to one side or the other slightly to give a slightly oblique x-ray image which can further delineate the anatomy.
- The procedure is now complete. The instruments are removed from the cervix and vagina.
- The woman usually remains on the table for a few minutes to recover from the cramping caused by injection of the contrast.
- The results of the test can be immediately available. The x-ray pictures can usually be reviewed with the woman several minutes after the procedure is done.
What risks are there from the test?
It is common for patients to have a small amount of bleeding from the vagina and some pelvic cramping for a few days after the procedure. If you have heavy bleeding, fever, or increasing pain in the pelvis, you should call your doctor. Some women experience an allergic reaction to the contrast dye. The most significant risk from this procedure is infection, which happens in close to 3 out of 100 patients. Most doctors use a water-soluble dye when they do this procedure; this dye does not usually irritate the uterus.
As with x-rays, there is a small exposure to radiation. In large amounts, exposure to radiation can cause cancers or (in pregnant women) birth defects. The amount of radiation from a hysterosalpingogram is too small to be likely to cause any harm. However, since the x-ray exposure is directed right at the pelvis and ovaries, it is very important to be sure you are not pregnant at the time of the test.
Does having a dye test improve the chance for getting pregnant?
Pregnancy rates in several studies have been reported to be very slightly increased in the first months following a hysterosalpingogram. This could be to the flushing of the tubes opening a minor blockage or cleaning out some debris that was preventing the couple from conceiving.
Some studies suggest that using oil based contrast provides a slightly larger increase in pregnancy success rates than the use of water based contrast. However, the large majority of HSGs are done with water based contrast.
HSG showing multiple “filling defects” in uterine cavity These represent numerous endometrial polyps The polyps were then removed by hysteroscopic resection
Abnormal study with a collection of dye in a “pocket” at the end of the left tube Scar tissue (adhesions) are holding the dye in the pocket Right tube was previously removed at surgery for a tubal pregnancy
Hysterosalpingogram picture showing uterus with a fibroid that is pushing in to the cavity Another fibroid on the outside of the uterus is circumscribed by dye along the red line Fibroids inside the cavity can cause infertility, miscarriage or preterm birth