What Is a Saline Sonogram (SIS)?
A saline sonogram, also known as saline infusion sonogram (SIS), sonohysterography (SHG), or saline ultrasound of the uterus, is a specialized ultrasound procedure used to evaluate the uterine cavity. During the test, sterile saline is introduced into the uterus through a thin catheter, helping to provide a clearer ultrasound image of the uterine lining and cavity. This test can detect polyps, fibroids, scar tissue (adhesions), and abnormal uterine shapes that may impact fertility or cause abnormal bleeding.
Saline sonograms are commonly recommended for people trying to conceive, experiencing unexplained infertility, recurrent pregnancy loss, or abnormal uterine bleeding. The procedure is generally well tolerated, minimally invasive, and provides valuable information for guiding further fertility treatment or investigation.
Key Takeaways
- A saline sonogram is an advanced ultrasound test that visualizes the uterine cavity using sterile saline.
- It can detect uterine abnormalities such as polyps, fibroids, or adhesions that may affect fertility.
- The procedure is also referred to as SIS, SHG, or saline infusion sonogram.
- Saline sonograms are used in fertility workups and may be recommended after abnormal bleeding or miscarriage.
- This test is usually performed in the first half of the menstrual cycle, after menstruation but before ovulation.
- Most people experience minimal discomfort, though mild cramping or spotting can occur.
- The SIS is different from an HSG (hysterosalpingogram), which assesses fallopian tube patency.
- Results are typically available immediately after the procedure, as the findings are visualized in real time.
- Saline sonograms are considered safe, with a low risk of adverse effects or complications.
- Costs vary—be sure to check with your clinic and insurance about pricing and coverage.
Table of Contents
- What Is a Saline Sonogram (SIS)?
- How Does a Saline Sonogram Work?
- Why Is a Saline Sonogram Used in Fertility Evaluations?
- What Can a Saline Sonogram Detect?
- Saline Sonogram vs. HSG: What’s the Difference?
- What to Expect During a Saline Sonogram
- Saline Sonogram Results: Reference Ranges and Interpretation
- Risks and Safety Considerations
- Saline Sonogram Cost: What Should You Expect?
- Ways to Reduce Discomfort During a Saline Sonogram
- When Should You See a Specialist About a Saline Sonogram?
- Frequently Asked Questions About Saline Sonogram (SIS)
- References and Further Reading
- Disclaimer
How Does a Saline Sonogram Work?
A saline sonogram (saline infusion sonogram, SIS, or sonohysterography) combines transvaginal ultrasound with the infusion of sterile saline into the uterus. Here’s how the test is typically performed:
- Pre-procedure Preparation: The test is usually scheduled after a person has completed menstruation but before ovulation (typically cycle days 6–12) to reduce the risk of disrupting an early pregnancy and to obtain the clearest view of the endometrial lining.
- Positioning: You will be asked to lie on an exam table in a position similar to a pelvic exam.
- Speculum and Catheter Placement: A speculum is inserted into the vagina, and a thin sterile catheter is gently guided through the cervix into the uterus.
- Saline Infusion: Sterile saline solution is slowly introduced through the catheter, expanding the uterine cavity and separating its walls.
- Ultrasound Imaging: A transvaginal ultrasound probe is inserted into the vagina, and images are obtained as the saline outlines the shape and any abnormalities of the uterine cavity.
- Post-procedure: The speculum and catheter are removed. You may experience mild cramping or spotting afterward but can generally resume normal activities right away.
Key Point: The saline acts as a contrast agent, highlighting irregularities in the uterine cavity that might be difficult to see with a basic transvaginal ultrasound.
Saline Sonogram (SIS) Quick Facts Table
| Feature | Description |
|---|---|
| Also Known As | SIS, saline infusion sonogram, SHG, sonohysterography |
| Purpose | To evaluate the uterine cavity for structural abnormalities |
| Procedure Type | Minimally invasive, in-office test |
| Timing | Early-to-mid follicular phase, after menstrual bleeding but before ovulation |
| Duration | Usually 15–30 minutes |
| Sample | None (uses ultrasound imaging and saline introduced via catheter) |
| Key Findings | Polyps, fibroids, adhesions, septum, congenital uterine anomalies |
| Associated Symptoms | May cause mild cramping, pressure, or brief spotting |
| Recovery | Immediate; normal activities can typically be resumed after the procedure |
| Risks | Low (mild infection, cramping, or spotting possible) |
| Cost | $250–$800+ per test (varies by clinic, location, and insurance) |
Why Is a Saline Sonogram Used in Fertility Evaluations?
A saline sonogram offers a detailed view of the uterine cavity that is crucial during infertility evaluations. Here’s why SIS is important for people trying to conceive:
- Detects Uterine Abnormalities: SIS can visualize small uterine polyps, submucosal fibroids, adhesions (Asherman’s syndrome), uterine septum, and other abnormalities that may be missed by standard transvaginal ultrasound. These findings are relevant as abnormalities within the cavity can interfere with implantation or increase the risk of miscarriage.
- Guides Further Treatment: If abnormalities are found, targeted treatments such as hysteroscopic polyp removal or surgical correction can be planned.
- Evaluates Unexplained Infertility or Recurrent Loss: For people with unexplained fertility challenges or recurrent pregnancy loss, ruling out structural uterine problems is a key step in the workup.
- Investigation After Abnormal Bleeding: When someone is experiencing irregular or postmenopausal bleeding, an SIS may help determine the cause.
Did you know? Up to 10% of people with infertility have a detectable cavity abnormality on SIS that may be treatable for improved pregnancy outcomes.[1]
What Can a Saline Sonogram Detect?
A saline sonogram is highly sensitive for identifying a variety of uterine abnormalities, including:
- Uterine Polyps: Benign overgrowths of endometrial tissue, sometimes contributing to infertility or abnormal bleeding.
- Fibroids (Leiomyomas): Benign muscle tumors of the uterus, especially those bulging into the cavity (submucosal).
- Adhesions (Intrauterine Synechiae): Scar tissue that may form after surgery, infection, or trauma (e.g., after miscarriage or D&C).
- Congenital Uterine Anomalies: Such as septate uterus or bicornuate uterus, which can affect pregnancy outcomes.
- Irregular Endometrium: Areas of thickening, thinning, or disruption that might indicate pathology.
Myths vs. Facts Table: Saline Sonogram
| Myth | Fact |
|---|---|
| "All uterine abnormalities show up clearly on regular ultrasound." | Some abnormalities, especially small polyps or subtle adhesions, are best seen with SIS. |
| "SIS can check if my fallopian tubes are open." | SIS assesses the uterine cavity, not tubal patency. HSG or HyCoSy are used for tubes. |
| "SIS is dangerous and painful." | The procedure is generally safe and only mildly uncomfortable for most people. |
| "I don’t need SIS if I’ve had a normal ultrasound." | Certain issues may only be detected with the saline contrast of SIS. |
Saline Sonogram vs. HSG: What’s the Difference?
Saline sonogram (SIS) and hysterosalpingogram (HSG) are both used in infertility workups but serve different purposes:
| Feature | Saline Sonogram (SIS/SHG) | Hysterosalpingogram (HSG) |
|---|---|---|
| Primary Use | Assessing uterine cavity structure | Assessing both uterine cavity and fallopian tubes |
| Medium | Sterile saline + ultrasound | Iodinated contrast dye + X-ray |
| Tube Assessment | No; tubes not directly visualized | Yes; tubal patency evaluated |
| Radiation Exposure | No | Yes (low dose) |
| Usual Discomfort | Mild cramping, brief | Mild to moderate cramping, brief |
| Contraindications | Suspected pregnancy, active infection | Same, plus iodine allergy |
Key Point: SIS provides a clearer view of the uterine lining’s contour, while HSG is more focused on whether the fallopian tubes are open.
What to Expect During a Saline Sonogram
Knowing what to expect can help reduce anxiety and discomfort:
- Preparation: You may be asked to take an over-the-counter pain reliever (like ibuprofen) 30–60 minutes before the test.
- Procedure Duration: SIS usually takes about 15–30 minutes, including preparation time.
- Sensation: You may feel mild cramping or fullness when the saline is infused. Some people report little to no discomfort; others may feel sensations similar to menstrual cramps.
- Recovery: Most people can return to work or normal activity immediately after. Light spotting or watery discharge is common for several hours post-procedure.
- Results Discussion: In many cases, the provider can share and explain findings right away.
Stepwise Process:
- Empty your bladder upon arrival.
- Change into a gown and get positioned.
- The provider inserts a speculum and cleans the vagina/cervix.
- A catheter is placed; speculum is removed.
- Saline is gently infused.
- The vaginal ultrasound probe is inserted, and images are taken.
- The procedure finishes; you may remain for a few minutes of observation.
Scenario Example: "Jordan was worried about discomfort, but felt only mild cramping during the saline sonogram and was able to drive themselves home after the appointment."
Saline Sonogram Results: Reference Ranges and Interpretation
A saline sonogram provides real-time visualization—not a numeric value—to evaluate the uterine cavity. Here’s what clinicians are looking for:
- Normal (Unremarkable): Smooth, intact endometrial cavity, no filling defects, adhesions, or abnormal contour.
- Polyps or Fibroids: Small, localized protrusions into the cavity.
- Adhesions/Synechiae: Irregular, “stuck together” areas of the uterine lining.
- Septate or Bicornuate Uterus: Double contours or partitions.
- Endometrial Thickening: May prompt further evaluation, especially in people with abnormal bleeding.
Did you know? Over 70% of SIS tests in routine infertility evaluation come back normal—so most people do not require further surgical intervention.[2]
Saline Sonogram Findings Interpretation Table
| Finding | Possible Implication | Fertility Impact | Next Steps |
|---|---|---|---|
| Normal cavity | No identified issues | Unlikely to cause infertility | Consider other causes; proceed as planned |
| Endometrial polyp | Benign growth may hinder implantation | May lower fertility | Hysteroscopic removal |
| Submucosal fibroid | May distort cavity or affect implantation | May lower fertility | Remove if symptomatic or large |
| Adhesions (synechiae) | Scar tissue can block menstruation, reduce fertility | Reduced fertility | Surgical removal (lysis of adhesions) |
| Septum/uterine anomaly | Congenital issue may increase miscarriage risk | Increases miscarriage risk | Surgical resection (metroplasty) as indicated |
Risks and Safety Considerations
A saline sonogram is considered safe, with a low risk profile. Possible side effects include:
- Mild uterine cramping or discomfort during the procedure
- Light vaginal spotting or watery discharge for several hours afterward
- Rarely, uterine or pelvic infection (<1 in 500 cases)
- Backflow of saline causing minimal, transient distension sensation
Risks vs. Ways to Reduce Risk Table
| Potential Risk | Ways to Minimize Risk |
|---|---|
| Infection | Aseptic technique; not performed if pelvic infection present |
| Discomfort or cramping | Pre-procedural pain relievers; gentle saline administration |
| Heavy bleeding or pain | Extremely rare; prompt evaluation if severe symptoms occur |
| Allergic reaction | No chemical dye used; rare allergic reaction |
Key Point: Notify your clinic if you experience severe pain, heavy bleeding, fever, or unusual discharge after the procedure.
Saline Sonogram Cost: What Should You Expect?
Saline sonogram pricing varies widely based on location, clinic, and insurance status:
- Typical Range: $250–$800 USD per procedure (not including fees for provider visit or additional tests).
- Insurance Coverage: Some policies cover SIS for infertility investigations or abnormal bleeding, but exclusions are common if performed primarily for fertility rather than symptom evaluation.
- Out-of-pocket: Those without insurance coverage should inquire about cash pricing, payment plans, and alternative billing options.
Did you know? Clinics often bundle SIS pricing into a comprehensive fertility assessment package, so ask for a full breakdown before scheduling.
Ways to Reduce Discomfort During a Saline Sonogram
While most people tolerate SIS well, mild cramping is common. Here’s how to minimize pain and anxiety:
- Take an over-the-counter pain reliever (ibuprofen or acetaminophen) 30–60 minutes before your appt.
- Practice deep breathing and relaxation techniques during the procedure.
- Ask your provider to use the smallest appropriate catheter and gentle technique.
- Request explanations of each step or distraction (music, conversation) if it helps.
- Tell your provider promptly if you feel significant pain or distress—they can slow down or pause.
Scenario Example: "Alex felt reassured by asking the clinician to explain each step and by taking slow breaths, making the experience more comfortable."
When Should You See a Specialist About a Saline Sonogram?
- If your provider suspects a uterine abnormality: Abnormal menstrual bleeding, unexplained infertility, or prior pregnancy losses may prompt SIS referral.
- Previous pregnancy complications: Recurrent loss, subfertility, or anatomic suspicion on other imaging.
- If you've had abnormal ultrasound(s): SIS provides further detail.
- After multiple failed IVF or IUI attempts: To rule out any hindrance to embryo implantation.
Whom to See:
- REI (reproductive endocrinologist and infertility specialist): For advanced fertility workups and procedures.
- Gynecologist: For evaluation of abnormal bleeding or reproductive tract issues.
- Radiologist: Sometimes they perform and interpret SIS, especially in non-fertility clinics.
Frequently Asked Questions About Saline Sonogram (SIS)
What does a saline sonogram (SIS) mean in fertility?
A saline sonogram is an ultrasound test using saline to visualize the inside of the uterus, helping to identify abnormalities affecting fertility. It is commonly used to check for fibrosis, polyps, or scarring that could interfere with conception or implantation.
SIS is a standard part of fertility evaluations and is particularly useful for people with recurrent pregnancy losses or unexplained infertility. By outlining the uterine cavity, it can help your care team tailor treatment to address specific barriers to pregnancy.
What is the difference between a saline sonogram and a hysterosalpingogram (HSG)?
A saline sonogram (SIS) uses saline and ultrasound to image the uterine cavity, while an HSG uses contrast dye and X-rays to check both the uterine cavity and whether the fallopian tubes are open.
SIS is mainly for uterine structure assessment, whereas HSG is for both uterine and tubal evaluation. Your doctor may recommend one or both, depending on your fertility workup needs.
Is a saline sonogram painful?
Most people report mild discomfort or cramping during a saline sonogram, similar to menstrual cramps. Pain is usually brief and resolves quickly after the procedure.
Individual experiences vary. Taking ibuprofen beforehand and communicating with your provider can help ensure comfort. Let your clinician know if pain is more than mild or does not resolve.
What can a saline sonogram detect that a regular ultrasound cannot?
A saline sonogram can better reveal subtle or small intrauterine abnormalities—like polyps, submucosal fibroids, or adhesions—by distending the uterine cavity with saline. Standard transvaginal ultrasounds may miss or under-characterize these findings.
Saline serves as a contrast agent, improving visibility of the cavity’s shape and any irregularities, allowing for more precise diagnosis.
When is the best time in the cycle to have a saline sonogram?
The optimal timing is the early follicular phase (cycle days 6–12), after menstrual bleeding but before ovulation occurs.
This window offers the clearest endometrial view and minimizes the risk of interfering with an early pregnancy. Your provider will help schedule the test at the right time for you.
Can a saline sonogram check if my fallopian tubes are open?
No, a saline sonogram primarily assesses the uterine cavity, not tubal patency. A small amount of saline may escape into the tubes, but this is not considered diagnostic for tubal openness.
A hysterosalpingogram (HSG) or saline/air contrast ultrasound (HyCoSy) is typically used for direct tubal evaluation.
How soon are saline sonogram results available?
SIS results are available immediately in most cases, as the provider reviews the ultrasound images in real time during the procedure.
Any findings will be discussed with you either during or shortly after the procedure. Sometimes a written report may follow, especially if additional review is needed.
How much does a saline sonogram cost?
Costs can range from $250 to $800 or more, depending on your region, clinic, and insurance coverage.
Call your clinic and check your insurance benefits before the test to avoid surprises. Many clinics offer package pricing as part of a fertility workup.
Are there risks or side effects with saline sonogram?
Risks are very low. Mild cramping, light spotting, or watery discharge are the most common side effects. Infection is rare, and allergic reactions are extremely unlikely, as only saline is used.
Serious complications are extremely rare but should be reported, such as heavy bleeding, severe pain, or fever.
Does a saline sonogram affect fertility in the cycle performed?
No evidence suggests saline sonogram itself impairs fertility or conception in the same cycle. However, since it’s scheduled before ovulation, conception attempts usually resume immediately afterward.
In rare cases, minor spotting/bleeding may slightly shorten the “fertile window,” but no harmful effects are expected.
Is sedation or anesthesia required for a saline sonogram?
No, sedation or general anesthesia is not necessary for this procedure. Most patients tolerate the test well with only minor discomfort.
If you have a history of cervical stenosis or pain, inform your provider—adjustments can be made for your comfort.
Is the saline used in a saline sonogram safe?
Yes, sterile saline is widely used and very safe. Allergic reactions are extremely rare, and the solution is not retained in the body.
Any excess fluid typically passes out of the vagina shortly after the test.
Can I return to work and normal activity after a saline sonogram?
Yes, most people can resume normal activities, including work, exercise, and intercourse, immediately after the procedure.
There are no specific activity restrictions unless your provider advises otherwise.
How should I prepare for a saline sonogram?
Follow your clinic’s instructions, which may include taking a pain reliever beforehand and arriving with an empty bladder.
Avoid intercourse from your period until after the procedure if there is a chance you could be pregnant, as SIS is not performed during pregnancy.
What if my saline sonogram shows an abnormality?
Your provider will discuss specific findings and their possible impact on fertility or bleeding concerns.
In most cases, treatment options—including follow-up imaging or minimally invasive surgery (hysteroscopic removal of polyps/fibroids/adhesions)—are available to address findings.
Are there alternatives to a saline sonogram?
Alternatives include hysteroscopy (direct visualization with a tiny camera), HSG (for tubal assessment), or MRI (for complex anatomic cases).
Your provider can help you understand the pros and cons of each based on your medical and fertility history.
Can SIS be performed if I’m on hormonal birth control?
Yes, but typically SIS is only indicated if you are having uterine bleeding or specific issues while using contraception, or if you are about to stop contraception before trying to conceive.
Inform your provider of all medications or hormonal treatments you are using.
Is SIS useful for everyone with fertility concerns?
Not always. SIS is most helpful when uterine cavity abnormalities are suspected or when initial workup suggests a structural problem.
Your fertility specialist will help decide whether the benefits outweigh the cost and invasiveness for your unique situation.
References and Further Reading
- Randolph JF Jr, Ying YK, Huneke AL, et al. Comparison of saline infusion sonography and hysterosalpingography for uterine cavity evaluation. https://pubmed.ncbi.nlm.nih.gov/10368579/
- de Kroon CD, Louwe LA, Trimbos JB, Jansen FW. Saline contrast hysterosonography in abnormal uterine bleeding: a systematic review and meta-analysis. https://pubmed.ncbi.nlm.nih.gov/12057786/
- American Society for Reproductive Medicine: Uterine cavity evaluation. https://www.asrm.org/globalassets/asrm/asrm-content/news-and-publications/practice-guidelines/for-non-members/uterine-cavity-evaluation-guideline.pdf
- Practice Committee of the American Society for Reproductive Medicine. Diagnostic evaluation of the infertile female: a committee opinion. https://pubmed.ncbi.nlm.nih.gov/24726289/
- Goldstein SR. Modern evaluation of the endometrium. https://pubmed.ncbi.nlm.nih.gov/10606964/
- Timor-Tritsch IE, Monteagudo A. Saline infusion sonohysterography (SIS): technique and clinical applications. https://pubmed.ncbi.nlm.nih.gov/7807399/
- World Health Organization (WHO) Infertility global epidemiology fact sheet. https://www.who.int/news-room/fact-sheets/detail/infertility
- ACOG Committee Opinion: The role of saline infusion sonohysterography in evaluating the endometrium. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2001/03/the-role-of-saline-infusion-sonohysterography-in-evaluating-the-endometrium
- National Institutes of Health: Hysterosonography. https://medlineplus.gov/ency/article/007480.htm
Disclaimer
This article is for informational and educational purposes only and does not constitute medical or mental health advice. It is not a substitute for speaking with a qualified healthcare provider, licensed therapist, or other professional who can consider your individual situation.
