SIS Test for Uterine Health: Decoding the Report

Saline infusion sonohysterography, also called SIS or a saline sonogram, is an ultrasound test that uses sterile salt water to show the inside of the uterus more clearly. Its report can help identify polyps, fibroids that affect the uterine cavity, scar tissue or differences in cavity shape. An abnormal finding does not automatically mean infertility or a need for surgery; your doctor interprets it alongside your symptoms and fertility history.

Why is an SIS test recommended?

The uterus is where an embryo implants and a pregnancy develops. A routine ultrasound provides useful information, but the two sides of the uterine lining usually lie close together. Gently introducing saline separates them, helping the doctor see the cavity’s outline and any tissue projecting into it.

Your doctor may recommend saline infusion sonohysterography when a routine scan suggests a cavity abnormality, or when you have unusual bleeding, repeated pregnancy losses or concerns during fertility treatment planning. It is not compulsory for every couple or before every treatment cycle.

At PRAVI IVF & Fertility Centre, Kanpur, discussing the reason for the test can help you feel more prepared. You can also explore our information on female infertility evaluation to understand how uterine assessment fits into the broader picture.

When and how is saline infusion sonohysterography done?

For someone with regular periods, SIS is usually scheduled after menstrual bleeding ends and before ovulation. The lining is relatively thin then, and pregnancy must be excluded. If your periods are irregular, ask your clinic how to time the test safely.

The examination usually begins with a transvaginal ultrasound. A speculum is then used to see the cervix, and a thin tube is passed through it. Sterile saline enters the uterus through the tube while ultrasound images are taken.

You may feel period-like cramps or pressure. Tell the clinician if you are uncomfortable; the examination can be paused or stopped if needed. Light spotting and watery leakage can occur afterwards.

How to prepare

• Share the date of your last period and any possibility of pregnancy.
• Tell the team about fever, unusual discharge, pelvic pain, recent infection or previous difficulty with pelvic examinations.
• Ask whether you should take a pain reliever beforehand; do not start antibiotics yourself.
• Bring previous ultrasound reports and records of uterine surgery, miscarriage care or fertility treatment.
• Carry a sanitary pad for fluid leakage or spotting after the test.

SIS should not be performed during pregnancy or an active pelvic infection. Significant ongoing bleeding may also affect visibility or lead your doctor to reschedule it. Our guide on preparing for fertility tests can help you organise your visit.

Decoding the main parts of your SIS report

Reports vary in wording. Rather than focusing on one unfamiliar term, look for what was seen, where it was located and whether the cavity was clearly assessed.

“Normal cavity” or “no intracavitary lesion”

This usually means the cavity looked smooth and no obvious growth or scar tissue was seen within it. It is reassuring about the structures examined, but it does not guarantee implantation or rule out every cause of infertility. Egg-related factors, sperm health, ovulation and tubal problems need separate consideration.

Endometrial thickness and appearance

The endometrium is the lining of the uterus. Your report may describe its thickness and whether it appears uniform. The lining changes naturally throughout the menstrual cycle, so a measurement needs to be interpreted with the cycle day, bleeding history and any hormonal medicines.

There is no single SIS lining measurement that can declare every person’s uterus “ready” or “not ready” for pregnancy. An irregular or unexpectedly thick lining may need further assessment, but ultrasound alone cannot diagnose abnormal cells.

Endometrial polyp

A polyp is a localised growth of the uterine lining that may appear as a smooth projection into the saline-filled cavity. Polyps are often benign and may occur with spotting, heavy periods or no symptoms at all.

Your doctor considers its size, location, your symptoms and treatment plans before recommending observation or removal. Not every suspected polyp requires the same approach.

Submucosal fibroid or cavity distortion

A fibroid is a usually benign growth arising from the uterine muscle. “Submucosal” means it extends towards or into the uterine cavity. SIS can help show how much it projects into the space where a pregnancy would develop.

Location matters: a fibroid that distorts the cavity may have different implications from one on the outer surface of the uterus. Further imaging may be needed to plan treatment. The word “fibroid” alone is not a reason to assume surgery is necessary.

Adhesions or synechiae

These terms describe bands of scar tissue inside the uterus. The report may mention bands crossing the cavity or areas that do not open normally with saline. Adhesions can occur after procedures involving the uterus or certain infections.

If scar tissue is suspected, hysteroscopy may be recommended to confirm the finding and discuss treatment. Your history, including lighter periods after a uterine procedure, can help the doctor interpret the images.

Septum or unusual cavity shape

A septum is a partition of tissue within the uterus. If SIS suggests a septum or another shape difference, additional assessment may be needed to understand both the internal cavity and the outer uterine contour.

Three-dimensional ultrasound or, in selected cases, MRI can help distinguish different uterine shapes. Treatment decisions should follow a confirmed diagnosis and a discussion of your reproductive history, rather than one report phrase.

“Limited study” or “inadequate distension”

This means the doctor could not assess the cavity fully. Possible reasons include fluid leaking through the cervix, difficulty passing the tube, discomfort or blood obscuring the view. It does not, by itself, confirm a uterine abnormality.

The next step may be repeat imaging at a different time or another examination, depending on why the view was limited.

What an SIS test cannot tell you

Standard saline infusion sonohysterography mainly assesses the uterine cavity. It does not measure egg quality, test embryo chromosomes or reliably exclude endometriosis.

It also should not be confused with a dedicated fallopian tube patency test. Fluid seen in the pelvis may suggest that at least one tube is open, but standard SIS does not reliably confirm that both tubes are open. Ask whether your planned examination is SIS alone or includes a specialised tubal assessment.

SIS provides images, not a tissue diagnosis. If a finding needs sampling, your doctor will explain whether a biopsy or another procedure is appropriate.

What happens after an abnormal SIS report?

The next step depends on the finding and your circumstances. Your doctor may suggest observation, more detailed imaging or hysteroscopy. During hysteroscopy, a thin camera allows direct inspection of the cavity; some abnormalities can also be treated during the procedure.

An abnormal report does not automatically mean that IVF is needed or that fertility treatment must stop. Equally, a normal report does not mean that other investigations are unnecessary. The aim is to choose a next step that answers a clear clinical question.

Questions worth asking at your review

• Was the whole uterine cavity clearly visible?
• Could this finding explain my symptoms or affect my treatment plan?
• Do I need confirmation before deciding on treatment?
• What are the benefits and risks of treatment versus observation?
• Does this change the timing of trying naturally or starting fertility treatment?

Aftercare and warning signs

Mild cramps, light spotting and watery discharge usually settle shortly after SIS. Follow your clinic’s instructions about activity, intercourse and pain relief. Infection is uncommon, but contact your treating team promptly for fever, worsening or severe pelvic pain, foul-smelling discharge or heavy bleeding. Seek urgent care if you feel faint or seriously unwell.

Medical terms can feel overwhelming, especially when you are already handling fertility concerns. Your SIS report is one piece of information, not a verdict on your chances of becoming parents.

For a personalised discussion of your report at PRAVI IVF & Fertility Centre, Kanpur, book an appointment or WhatsApp +91 80091 50040. Bring your report and previous records so the team can help you understand the next appropriate step.