What is it?
Saline Infusion Sonohysterography (SIS) or saline ultrasound uterine scan uses a small amount of saline (salt
solution) inserted into the uterus (or womb) that allows the lining and cavity of the uterus (endometrium) to be clearly seen on an ultrasound scan.
The SIS test is performed by an obstetrician sonologist with specialist skills in carrying out this type of
procedure. A sonologist is a registered obstetrician and gynaecologist who has undertaken additional sub-specialty training and qualifications in performing and making diagnoses from ultrasound
examinations and procedures.
Who should have the procedure?
SIS helps to see if there is any thickening or small growths (polyps) of the endometrium of the uterus that may
have been seen on a prior pelvic ultrasound scan. SIS can also be carried out to assess the postmenopausal endometrium in patients who have postmenopausal bleeding.
How is the procedure performed?
On the day of the procedure a transabdominal and/or transvaginal (internal) ultrasound is performed prior to
the procedure. Before the procedure commences your bladder will need to be emptied completely.
For the procedure itself a speculum will be placed in the vagina and the cervix cleansed with antiseptic. A
fine soft plastic tube (catheter) is passed through the cervix into the uterus.
The speculum is then removed while the catheter still remains in the uterus, and a transvaginal ultrasound
transducer is inserted into the vagina.
The transducer is especially shaped to fit comfortably into the vagina. A protective sterile probe cover is
placed over the transducer and lubricating gel is applied to it for ease of insertion.
A small amount of saline (salt solution) is inserted through the catheter into the uterine cavity. During and
after the saline injection, the transducer is then gently moved around while images of the inside of the uterus are taken.
The saline fluid within the uterus allows the lining of the uterine cavity to be imaged clearly on the
Is it safe?
The procedure is safe. There is a small risk of introducing infection into the uterus and pelvis. If
you develop symptoms of fevers, loss of appetite, pelvic pain, unusual vaginal discharge in the days following the procedure, please see your referring doctor for further
Very occasionally, handling of the cervix results in a reflex fall in blood pressure, and a fainting episode
(cervical shock). If you are feeling faint or experiencing loss of vision or hearing during the procedure, please alert the doctor performing the procedure.
How to best prepare for the procedure?
You will be asked to go to the toilet and empty your bladder before the scan. If you are using a tampon, it
will need to be removed. You can still have the scan if the period is just finishing and bleeding is light.
When in my cycle can I have the procedure?
The scan is best done as your period finishes, day 4-10 of your menstrual cycle. So, it is best to arrange your
appointment according to your period dates.
An SIS scan cannot be carried out if you are pregnant or if you have had pelvic inflammatory
You will be asked to complete a consent form on the day of the procedure.
How will I feel after the procedure?
After the scan, there is a small trickle of fluid from the vagina. This is the saline fluid that was inserted
through the catheter coming out. It is commonly slightly blood stained and this may continue for 24 hours. You may wish to use a sanitary pad, but you are advised not to use tampons for the rest of
Most patients feel normal after the scan with no after effects. Some patients may have some pelvic discomfort
(like mild period pain), but this settles after a few minutes up to perhaps an hour or so, and is very uncommon.
A very small number of patients may have some discomfort due to the cervix and uterus being slightly irritated
by the catheter. This usually passes within a few minutes and has no adverse outcome.
You will generally be well enough to drive home and resume normal activities, such as going back to
How long do the results take?
The doctor performing the procedure will send a written report of the findings to your referring doctor on the
day of the procedure. You will be able to discuss the results at your next appointment with your referring doctor.