A hysterosonogram is an ultrasound procedure that uses sterile saline (salt water) to get a detailed view of the inside of your uterus. It goes by several names, including sonohysterography and saline infusion sonography. The saline gently expands the uterine cavity, making the lining and any abnormalities much easier to see than on a standard ultrasound. The whole process typically takes about 15 to 30 minutes and is done in a doctor’s office or imaging center.
How the Procedure Works
On a regular transvaginal ultrasound, the walls of the uterus press together, which can hide small growths or other problems. During a hysterosonogram, a thin catheter is inserted through the cervix and a small amount of sterile saline, usually 10 to 15 milliliters, is slowly pushed into the uterine cavity. The fluid separates the walls and creates contrast on the ultrasound screen, giving your provider a real-time, detailed picture of the uterine lining and cavity shape.
A small balloon on the catheter tip prevents the saline from leaking back out through the cervix, which keeps the cavity expanded long enough for a thorough exam. Because the procedure uses saline rather than contrast dye, there’s no risk of an allergic reaction to imaging agents.
Why Your Doctor May Order One
The most common reason for a hysterosonogram is abnormal uterine bleeding, whether that means unusually heavy periods, bleeding between periods, or postmenopausal bleeding. The test is specifically designed to detect problems inside the uterine cavity that a standard ultrasound might miss. According to the American College of Obstetricians and Gynecologists, indications include:
- Polyps, fibroids, or scar tissue inside the uterine cavity
- Infertility or recurrent pregnancy loss, to check for structural problems
- Congenital uterine abnormalities like a uterine septum
- Unclear findings on a previous transvaginal ultrasound
- Pre-IVF screening to make sure the cavity is normal before embryo transfer
How Accurate Is It?
A hysterosonogram is highly reliable for spotting problems inside the uterus. One study comparing it against tissue biopsy found diagnostic accuracy of 99% for fibroids that bulge into the cavity, 90% for endometrial polyps, and 94.4% for abnormal thickening of the uterine lining. These are strong numbers, which is why the test has become a go-to for evaluating the uterine cavity before more invasive procedures.
Hysterosonogram vs. Other Imaging Tests
A standard transvaginal ultrasound can measure the thickness of the uterine lining and identify large fibroids, but it often can’t distinguish between a polyp and a fibroid, or tell whether an abnormality is inside the cavity versus within the uterine wall. The saline infusion step solves that problem by outlining the cavity in detail.
A hysterosalpingogram (HSG) is a different test that uses X-ray and contrast dye. Its main strength is evaluating whether the fallopian tubes are open, which is critical in fertility workups. However, research consistently shows that a hysterosonogram is more sensitive, specific, and accurate than an HSG for detecting problems inside the uterus itself, including polyps, fibroids, adhesions, and structural abnormalities. In many fertility evaluations, both tests are used: the HSG to check the tubes, and the hysterosonogram to check the cavity.
When It’s Scheduled
Timing matters. The test is best done in the first half of your menstrual cycle, after your period ends but before ovulation. That typically falls between days 6 and 11 of your cycle. There are two reasons for this window: the uterine lining is at its thinnest, making abnormalities easier to spot, and it minimizes the chance of performing the procedure during an early pregnancy.
How to Prepare
Preparation is minimal. You’ll want to wear comfortable, two-piece clothing since only your lower abdomen needs to be accessible. If you haven’t had a pelvic ultrasound recently, you may be asked to drink about a quart of water an hour beforehand so your bladder is full for initial imaging. Once the transvaginal portion begins, you’ll empty your bladder. Some providers recommend taking an over-the-counter pain reliever like ibuprofen about 30 to 60 minutes before your appointment to reduce cramping.
What It Feels Like
Most people describe the sensation as similar to menstrual cramps. You’ll feel the speculum insertion (like a Pap smear), then mild to moderate cramping as the catheter goes through the cervix and the saline fills the cavity. The cramping is usually brief. Some people barely notice it, while others find it uncomfortable but tolerable. The actual imaging portion, once the saline is in place, is painless.
After the procedure, you can expect some cramping and watery discharge as the saline drains out over the next few hours. Most people return to normal activities the same day.
Who Should Not Have One
There are three main situations where this test should not be performed: if you’re pregnant, if you have an active pelvic infection, or if you have an intrauterine device (IUD) in place. An active infection is the most critical concern, because pushing fluid through the cervix could spread bacteria into the uterus or fallopian tubes. Providers typically screen for signs of infection before proceeding.