Endometrial Polyp: Saline Ultrasound or Hysteroscopy?

Both saline infusion sonohysterography (saline ultrasound) and hysteroscopy are excellent tools for evaluating uterine polyps, but they serve different primary purposes. Saline ultrasound is an imaging test used to clearly see if a polyp is present, while hysteroscopy allows a doctor to look directly inside the uterus and, in many cases, remove the polyp to test it.

Most polyps are benign (noncancerous) growths of the uterine lining (endometrium), but further testing is often needed because imaging alone cannot definitively prove a polyp is harmless ^[1][2].

The Baseline: Transvaginal Ultrasound

A standard transvaginal ultrasound (TVUS)—where an ultrasound wand is placed in the vagina—is usually the first step for evaluating abnormal bleeding or pelvic pain ^[3]. However, a standard ultrasound only detects about 55% to 62% of polyps when they are present (its sensitivity) ^[1][4]. Because the walls of the uterus naturally touch each other, small polyps can easily hide. If your symptoms persist but a standard ultrasound is unclear, your doctor will likely recommend a more detailed test ^[4][3].

Saline Infusion Sonohysterography (Saline Ultrasound)

Saline infusion sonohysterography (SIS) involves gently inserting a small amount of sterile saltwater (saline) into the uterus through the cervix before taking ultrasound pictures. The fluid gently expands the uterine cavity so polyps stand out clearly.

• Diagnostic Value: Saline ultrasound is excellent at finding polyps, correctly identifying them in about 87% to 92% of cases in research studies ^[1][4].
• Advantages: It is an effective way to improve the ultrasound image without sedation ^[5]. It is relatively inexpensive and successfully completed in most patients ^[6][1].
• Limitations: It is strictly an imaging test. It cannot provide a tissue sample to evaluate for abnormal cells, nor can it remove the polyp ^[1][7]. If a polyp is found, you may need a separate procedure to remove it ^[7].

Diagnostic and Operative Hysteroscopy

Hysteroscopy uses a hysteroscope—a thin, lighted tube with a camera—inserted through the vagina and cervix directly into the uterus.

• Diagnostic Value: Hysteroscopy also has a high sensitivity for detecting polyps (around 92%) ^[1].
• Advantages: It provides a direct view of the lesion. More importantly, it often allows for a “see and treat” approach: your doctor can use tiny instruments to remove the polyp (polypectomy) and send it to a pathologist ^[8][9]. This is especially valuable for focal lesions, as a visually directed biopsy is much more reliable than a “blind biopsy” (where tissue is sampled without a camera, which can easily miss a small polyp) ^[2][10].
• Limitations: Same-day removal is not always possible; a polyp may be too large or difficult to access in a clinic setting ^[11].

What to Expect and Risks

Neither test should be performed if you might be pregnant or have an active pelvic infection.

• Saline Ultrasound: You may experience mild to moderate cramping and spotting. Complications are extremely rare but can include infection or a vasovagal reaction (feeling faint) ^[6].
• Hysteroscopy: Office hysteroscopy can cause cramping, pressure, and spotting. While many tolerate it well with over-the-counter pain medication or local cervical anesthesia, it is not suitable for everyone ^[11][9]. If you have a history of painful pelvic exams or severe anxiety, you and your doctor can discuss options like oral sedation, or scheduling the procedure in an operating room ^[12]. Rare complications include infection, bleeding, or uterine perforation (a small tear in the uterine wall) ^[13].

When to Seek Care: After either procedure, contact your doctor immediately if you develop a fever, foul-smelling discharge, severe or worsening pelvic pain, heavy bleeding, or fainting.

Comparing the Tests

How to Choose What Is Right for You

Your evaluation depends on your unique health profile, balancing the need for tissue testing with your preferences.

• Bleeding Symptoms and Menopause: Most polyps are benign. However, population estimates suggest that polyps are more likely to contain precancerous or cancerous cells in women who have gone through menopause (about 4.9%) compared to premenopausal women (about 1.1%) ^[14]. Symptomatic bleeding also increases this risk ^[14]. If you have postmenopausal bleeding, your doctor may recommend moving to endometrial sampling or hysteroscopy to evaluate the tissue ^[2][11].
• Other Risk Factors: Factors like being over age 60, obesity, diabetes, or high blood pressure can also lower the threshold for doing a tissue biopsy ^[15][10].
• Fertility Goals: If you are trying to get pregnant, an office hysteroscopy can diagnose and remove a suspected polyp in one step, which may improve your chances of pregnancy ^[11][16]. However, not every polyp requires immediate removal, and you should discuss timing and alternatives with your doctor ^[11].