SIS (Saline Sonography)
What is an SIS?
Saline sonography also known as SIS is an ultrasound procedure using contrast fluid – usually a salty water solution known as saline – to assess the pelvis. SIS measures the direction and length of the entrance to the womb to determine:
- Which catheter (or tube) is needed to gently introduce the embryo’s into the womb, if applicable
- The depth at which the embryo’s should be inserted to maximise your chance of a successful treatment and
- The number of embryos for transfer.
SIS also confirms that the inside of the womb (also called the endometrial cavity) has no abnormalities within it – such as polyps or sub-mucous fibroids, which could hinder the embryos from implanting in the womb. SIS may be used to confirm wither x-foam can pass through the fallopian tubes into the pelvis to confirm that one or more are not blocked.
How is SIS performed?
It is an outpatient procedure, which takes less than half an hour to perform. It is usually done after menstruation has ended but before ovulation (to prevent interference with early pregnancy). It can be performed at any time of the cycle if the patient is on the oral contraceptive pill.
If you think you may be pregnant, take a pregnancy test and inform Rotunda IVF prior to your SIS.
A small catheter is passed into the womb to allow the water to be placed into the womb. This profiles the cavity to confirm normality. The absence of any fluid before the test followed by the presence of fluid in the pouch of Douglas (a space behind the womb) afterwards confirms the patency of the fallopian tubes.
The ovaries are also imaged. This test is not designed to diagnose endometriosis unless there is an endometriotic cyst present (endometrioma).
After SIS, the patient can immediately resume normal activities although some doctors ask that the patient refrain from intercourse for a few days. Instructions are given to the patient before discharge.
Is it uncomfortable?
It may cause mild or moderate cramping for about five minutes and some patients may experience cramps for several hours.
What are the risks and complications of SIS?
SIS is a minimally invasive procedure with low risk of complications and a high level of efficiency. Other tests, like hysteroscopy, laparoscopy or hysterosalpingography can be carried out for the same purpose as SIS which may provided additional information. However, these procedures are more invasive, may require use of either general anaesthesia or ionic radiation (X-ray) and also bring additional risks. We generally do not use them as an initial assessment tool, unless specifically indicated.
There is a small (about 1 in a 100) risk of pelvic infection resulting from this test and so you will be asked to take antibiotics to minimise this risk.
The consequences of such infection – especially if there is pre-existing infection or tubal damage – could include infection, swelling and blockage of the fallopian tubes or other structure in the pelvis or abdomen which an (rarely) require surgery.
It is possible to develop a reaction to any drugs given before, during, or after the procedure.
After an SIS
The effects of an SIS are generally minimal so routine activity afterwards is normally recommended.