What to Know When Your OB-GYN Recommends Saline Infusion Sonography

A closer look at getting a SIS
woman in doctor's office finding out about SIS procedure

If you’ve ever experienced irregular, heavy or post-menopausal bleeding, struggle with infertility or had an ultrasound and something came up abnormal, or the cavity was not clearly seen, your doctor could order a saline infusion sonography (SIS). This special ultrasound gives your doctor a better look at your uterus, especially the cavity.

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What exactly is a SIS and what does it involve? Gynecologist Oluwatosin Goje, MD, explains all the nuances that come with getting a SIS.

A closer look

The procedure itself goes quickly and usually doesn’t hurt, says Dr. Goje.

A SIS is similar to the transvaginal ultrasound that’s often performed, but with one added step: Sterile fluid is used to gently expand and hold the walls of your uterus apart. This helps your doctor get a better view of the uterine cavity and any irregularities can be seen more clearly. It can also show whether there are any polyps, or abnormal tissue growths, extending inside the uterus, any fibroids pressing on the lining and whether the uterine cavity is normally shaped.

Your doctor will order a SIS for you if you:

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  • Had an ultrasound that was inconclusive and more views are needed
  • Struggle with infertility.
  • Have pelvic pain.
  • Have two or more miscarriages in a row.
  • Abnormal menstrual cramps.
  • Will be having IVF treatment.
  • Experience irregular or heavy and they are considering polyps or fibroids postmenopausal bleeding.

“A SIS is a very safe procedure and complications from the procedure are rare,” says Dr. Goje. “You may feel a slight discomfort when the fluid is gently introduced into the uterine cavity. The most common complication is pelvic infection, but this is rare.” 

There isn’t much you have to do to prepare for a SIS. To avoid accidentally doing the procedure in early pregnancy, Dr. Goje recommends getting it done after your period ends but before you ovulate. 

“A SIS is performed between day 6 to 11, considering the first day of menstrual bleeding as day 1,” says Dr. Goje.

If you’re pregnant, your doctor won’t schedule a SIS for you.

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Your doctor may suggest you take acetaminophen or ibuprofen (Advil®, Motrin®) before the procedure. But if you prefer a different medication or have allergic reactions to the listed medications, talk to them about your options.

5 things to expect during the procedure:

  1. First, a sterile speculum is placed in the vagina, just like for a Pap test. The cervix is visualized and the cervix and vagina are cleaned off with a soap solution. Then, a soft flexible tube, thinner than the inside of a pen, is passed into the uterus via the cervix. Most people don’t feel this at all while some feel it minimally. Sometimes your doctor may provide a medication in advance to soften the cervix in post-menopausal women for ease of passage of soft flexible tube.
  2. The speculum is removed and the ultrasound probe inserted. While the ultrasonographer takes images of the uterus, sterile liquid is gently injected through the thin tube, or catheter. You may feel a little bloating or cramping, but most women don’t feel much.
  3. After the pictures are recorded, the probe and the catheter slip right out.
  4. When you sit up after the procedure, you’ll probably feel lots of water coming out onto the sheet you are sitting on. Many patients wear a pad home, just in case there is any further dripping. Sometimes fluid may be blood-tinged or pink in color due to the disruption of the lining or wall of the uterus. This is usually self-limited.
  5. The results of the scan are shared with the referring doctor, who will use them to make a treatment plan for your specific situation.

A SIS will be able to help you be on your way toward the best treatment for you. Talk to your doctor to figure out if scheduling a SIS is your best option.

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