If you are having a transabdominal ultrasound, your bladder will need to be full. You’ll drink about 32 ounces — or four 8-ounce glasses — of water or another clear fluid at least 1 hour before the test. A full bladder makes your organs show up more clearly on the picture. You can use the bathroom after the procedure.
A transvaginal ultrasound is done with an empty bladder. You’ll use the bathroom before the test.
Wear lose, comfortable clothes to the exam. You might need to wear a gown during the procedure.