A saline sonogram, formally called a Saline Infusion Sonohysterography (SIS), is a specialized imaging technique used to get a clear view of the inside of the uterus. This procedure involves using a standard transvaginal ultrasound while gently introducing a small amount of sterile saline solution into the uterine cavity. The fluid acts as a contrast agent, temporarily expanding the uterus and creating a sharp outline of the uterine lining, known as the endometrium. This allows providers to detect minor abnormalities that might be missed during a routine ultrasound examination.
Why is the Procedure Necessary?
A healthcare provider recommends a Saline Infusion Sonohysterography (SIS) to investigate symptoms or conditions related to the uterine cavity. The procedure is effective for evaluating abnormal uterine bleeding, especially bleeding between periods or after menopause, by clearly visualizing the cavity to pinpoint the cause.
The SIS procedure is frequently used in fertility evaluations, particularly for patients experiencing infertility or recurrent miscarriages. It is the preferred method for detecting structural issues like small uterine polyps (growths on the lining) or submucosal fibroids (benign muscular tumors). The procedure also helps identify intrauterine adhesions, which are bands of scar tissue that can interfere with conception or pregnancy.
Understanding the Procedure Steps
The procedure begins with the patient positioned on an examination table, similar to a standard gynecological exam. The provider first performs a preliminary transvaginal ultrasound to establish baseline images of the uterus and ovaries. Next, a speculum, the same instrument used for a Pap smear, is gently inserted to provide access to the cervix.
The cervix is cleansed with an antiseptic solution before a thin, flexible catheter is passed through the cervical opening into the uterine cavity. This insertion may cause a brief, sharp sensation. Once the catheter is in place, the speculum is removed, and the transvaginal ultrasound probe is reinserted. The probe is lubricated for comfortable insertion.
The sterile saline solution is then slowly infused through the catheter into the uterus. As the fluid fills the cavity, the provider simultaneously uses the ultrasound probe to capture real-time, detailed images of the uterine walls and lining. The entire process of catheter insertion, saline infusion, and imaging is typically completed within a few minutes.
Managing Discomfort and Pain Relief
The most common sensation experienced during a saline sonogram is mild to moderate menstrual-like cramping. This cramping is caused by the uterus distending, or stretching, as the saline solution is infused to open the cavity for visualization. The sensation usually peaks during the brief period when the fluid is flowing into the uterus.
To minimize this discomfort, patients are advised to take an over-the-counter non-steroidal anti-inflammatory drug (NSAID), such as ibuprofen, about 30 to 60 minutes before the procedure. This pre-emptive medication helps reduce the muscle contractions that cause the cramping sensation. Focusing on slow, deep breathing during the fluid infusion can also help manage the feeling of pressure or cramping.
Because the procedure is quick, the most uncomfortable part is short-lived and tolerable for most people. Once imaging is complete, the catheter and probe are removed, and the cramping sensation often subsides rapidly. It is common to experience light spotting and mild, residual cramping for a few hours afterward as the saline naturally drains from the uterus. Severe, worsening pain, heavy bleeding, or a fever are rare side effects and require immediate contact with the healthcare provider, as they could indicate an infection.