A sonohysterogram is done to diagnose irregular or heavy bleeding, to find out if there are fibroids or polyps in the uterine cavity, commonly called the lining. Your practitioner will place an appropriately sized speculum into your vagina and then thread a small catheter through your cervix. You may experience cramping as a tiny balloon is inflated to hold the catheter inside your uterus. The speculum is removed and a vaginal ultrasound probe will be gently placed. Your practitioner will inject fluid through the catheter into the uterus. The fluid separates the walls of the uterus so your practitioner can see any growths which might otherwise be hidden from view.