A saline infusion sonogram is an ultrasound examination in which saline is introduced into the womb which shows up any scarring or irregularities in the cavity. It does not require an anaesthetic and is usually not unduly painful as long as the doctor performing the procedure does not use too much pressure.

An initial internal (transvaginal) ultrasound scan is performed. Some images may be recorded. The probe is then removed and a speculum is introduced into the vagina so that the cervix (neck of the womb) can be seen and a small plastic tube about 2mm in diameter is introduced into the cervix, rather like having a smear test for cervical cancer. A tiny balloon is inflated to keep it in place and then the speculum is removed and the ultrasound probe is reinserted. Saline is gently instilled whilst the uterus is being scanned and further images are taken. The whole procedure should only take about 15 minutes. There is no need to fast prior to the procedure.

Sometimes the cervical canal is difficult to cannulate or may be acutely retroverted, in which case te doctor may need to use a small clip called a tenaculum to stabilise or straighten out the cervical canal. This may cause further pain, like a period pain or cramp.

The image below shows the uterus filled with saline which appears black in the image. The 3 black and white images show the uterus in 3 planes and the golden image at bottom right is a 3D reconstruction of the uterus. This shows an area of tissue at the left cornual area of the uterus and a relative blockage in the cervical canal.