Sonohysterogram or Hysterosonogram

What is a sonohysterogram?

A hysterosonogram or HSN is also known by the names sonohysterogram, saline ultrasound, saline sonogram, or saline infusion sonogram. A hysterosonogram is a minimally invasive ultrasound procedure that can determine if there are abnormalities inside the uterus that might interfere with pregnancy. It is important to have an evaluation of the uterine cavity with a sonohysterogram or other method before proceeding with an IVF cycle. This test involves no radiation, and there are very few risks from the procedure. Compared to a regular ultrasound, a sonohysterogram is better at detecting abnormalities on the inside walls of the uterus because it involves infusing sterile fluid inside the uterus. This way, the walls of uterus separate from each other and any abnormalities that might have been hiding right along the sides of the walls will be easily identified.

Here is an example to help understand why we do a hysterosonogram. Think of your uterus like a collapsed balloon. If there was a small growth or bump on the inside wall of the collapsed balloon, it might be hard to see since the top and bottom walls are touching each other. However, if we inflated the balloon, the small growth will be easier to see since it will likely be able to hang away from the wall.

Traditionally, the “best” way to look for abnormalities inside the uterus was a test called a hysteroscopy, which involves an out-patient surgery using a type of telescope to look inside the uterus. However, in recent years, the techniques for a sonohysterogram have become so advanced that it has usually replaced hysteroscopy as the first procedure to look for abnormalities in the uterus. Compared to a hysteroscopy, a sonohysterogram is less invasive, less expensive and nearly as effective at detecting abnormalities.

What kind of problems can a hysterosonogram diagnosis?

A hysterosonogram is often recommended for women who are having difficulty conceiving a pregnancy or for women who are having recurrent miscarriages. In some cases, a hysterosonogram may be used for a woman who is having abnormal vaginal bleeding. Since a sonohysterogram gives such a detailed view of the inside walls of the uterus, it can identify many types of abnormalities that might prevent a normal pregnancy from developing. Studies have shown that it can detect over 90% of abnormalities inside the uterus. Some of these abnormalities include:

  • Polyps
  • Fibroids
  • Scar tissue
  • Uterine septum
  • Bicornuate Uterus

How is a sonohysterogram performed?

The procedure for performing a sonohysterogram is very simple and usually takes about 5 minutes. In order to schedule a sonohysterogram, you will need to call with the first day of your period. You will be given an appointment for some time point after the bleeding from the period has ended but before it is thought that ovulation might occur. This ensures that the uterine lining is as thin as possible. This is important since it will assist the doctor in visualization of the cavity. The hysterosonogram is performed in the office. Using a speculum, a very then, soft, flexible plastic catheter will be inserted through the vagina and cervix into the lower part of the uterine cavity. The speculum is then carefully removed so as not to disturb the catheter. A vaginal ultrasound probe is then placed into the vagina. Through the catheter, a small amount of saline (sterile salt water) is injected into the uterine cavity to separate the walls.

During a sonohysterogram, the ultrasound probe can be rotated to show the long axis of the uterus or a transverse axis. In the long axis, the uterine cavity appears long and ovoid.

Normal hysterosonogram

In the transverse view, the uterine cavity looks triangular.

Sonohysterogram normal

The saline appears dark black on the ultrasound. Abnormal growths in the uterine cavity will appear as ovoid, grey to white growths that protrude into the cavity. A cavity that is split will show the black appearing saline separated into two areas.

Hysterosonogram uterine septum

Sometimes after the procedure, a small amount of the saline fluid may leak out of the vagina. It is also possible that the patient may experience some bleeding or spotting. It is recommended that the patient wear a light pad or tampon for the rest of the day.

What do you need to do before a hysterosonogram?

Occasionally, a woman might experience some cramping during or after a hysterosonogram. If she desires, she may take 1-2 tablets of ibuprofen (Motrin or Advil) 1-2 hours before the procedure to decrease cramping. This may be repeated 3-4 hours later in the unlikely event that cramping persists.

What do you need to do after a sonohysterogram?

You will be able to watch the sonohysterogram on a monitor while it is being performed. Afterwards, the doctor will review the findings with you and answer any questions about those findings. If there are any abnormalities that are found on the inside of your uterus, don’t worry! Nearly all of these conditions are easily corrected with minimally invasive, outpatient surgery (usually with hysteroscopy).