Saline Sonography
A Saline Infusion Sonography is an advanced ultrasound scan examination to assess the uterine cavity in greater detail. It can help identify abnormalities that may affect fertility, implantation or pregnancy outcomes.
What is Saline Sonography?
A Saline Infusion Sonography is a fertility diagnostic procedure that uses sterile saline (water) and transvaginal ultrasound imaging to assess the uterine cavity.
The examination allows us to identify anatomical abnormalities, as well as any scar tissue, polyps, or fibroids that may affect your fertility.
Results are usually available immediately and will be discussed with you at the time of the examination, together with recommendations for any further investigations or treatment where appropriate.
What to Expect
Saline sonography is a safe, well-tolerated outpatient procedure performed in the clinic. The examination typically takes between 20 and 30 minutes.
The procedure is usually performed during the first half of the menstrual cycle, once menstrual bleeding has stopped and before ovulation has occurred.
A transvaginal ultrasound scan is first performed. A fine tube (catheter) is then gently passed through the cervix into the uterine cavity, and a small amount of sterile saline is introduced. The saline separates the uterine walls, allowing detailed assessment of the uterine cavity and endometrium.
The saline solution does not affect future fertility and is safely absorbed by the body. Most patients experience only mild discomfort, similar to period cramps or a cervical smear test. Some light spotting may occur following the procedure.
FAQs
Why might I need a saline sonography?
The uterus is where an embryo implants and develops, so its condition is central to fertility. Even minor abnormalities inside the cavity can reduce the chances of successful implantation or increase the risk of miscarriage, sometimes without causing any obvious symptoms. Saline sonography allows us to accurately identify abnormalities and plan accordingly.
At Genus Fertility, we may recommend a saline sonography as part of your initial fertility investigation, before starting an IVF or IUI cycle, or if a standard ultrasound has raised a question that needs a closer look.
Is it painful?
Most people find it similar in sensation to a smear test or a mild period cramp. Discomfort tends to occur when the catheter passes through the cervix and when the saline is introduced. It is generally well tolerated, though individual experience varies.
We recommend taking two paracetamol one hour before your appointment to help manage any cramping. You can drive yourself to and from the clinic, return to normal activities the same day, and may notice a small amount of watery discharge afterwards as the saline drains, which is entirely normal.
What conditions can saline sonography detect?
A saline sonography is an extension of a standard transvaginal ultrasound examination that uses sterile saline to provide additional information about the uterine cavity and endometrium.
The examination can help identify a range of abnormalities affecting the uterine cavity. Common findings may include:
Endometrial Polyps
Small growths arising from the lining of the uterus. Polyps can interfere with embryo implantation and are a common finding during fertility investigations.
Submucosal Fibroids
Benign muscle tumours that protrude into the uterine cavity. Depending on their size and location, they can distort the cavity and reduce the chances of implantation or successful pregnancy.
Intrauterine Adhesions (Asherman’s Syndrome)
Bands of scar tissue within the uterine cavity, sometimes occurring after surgery, infection or pregnancy-related procedures. These can affect both fertility and menstrual function.
The scan also provides a detailed assessment of the uterine cavity and endometrium, helping guide further investigations and treatment planning where appropriate.
How is saline sonography different from a standard ultrasound or a HyCoSy?
These are three distinct investigations that serve different purposes, and it is worth understanding how they differ.
A standard transvaginal ultrasound gives us a general overview of the uterus, ovaries, and surrounding structures. It is useful for assessing ovarian reserve, follicle development, and obvious structural concerns, but the uterine cavity walls are closely apposed and difficult to examine in fine detail without distension.
Saline sonography focuses specifically on the uterine cavity. The saline separates the walls, allowing us to examine the endometrial lining closely for polyps, fibroids, adhesions, and other structural abnormalities.
A HyCoSy uses a contrast fluid to assess whether the fallopian tubes are open and patent, as well as providing some information about the uterine cavity. Where the primary concern is tubal patency, a HyCoSy is the more appropriate test. Where the focus is on the uterine cavity itself, saline sonography offers greater detail and accuracy.
In some cases, both investigations may be recommended as part of a comprehensive fertility assessment.
If an abnormality is found, what happens next?
If an abnormality is identified, the significance of the finding will depend on its type, size, location and your individual fertility history. Not all abnormalities require treatment, and management recommendations are always tailored to your circumstances.
Some findings, such as endometrial polyps, submucosal fibroids or intrauterine adhesions, may affect implantation or pregnancy outcomes and can sometimes be treated with a hysteroscopy. This is a minimally invasive procedure that allows direct examination of the uterine cavity through the cervix and, where appropriate, treatment of identified abnormalities.
In other cases, no intervention may be required, and the finding may simply help guide treatment planning or provide reassurance regarding the uterine cavity.
If your saline sonography is normal, this is a reassuring result and suggests that the uterine cavity is unlikely to be contributing to difficulties conceiving or maintaining a pregnancy.