What to do if i have a pelvic ultrasound they sent me to go drink more then come back at 12:45 ?

Do as they ask: A transabdomial pelvic ultrasound requires a maximally distended urinary bladder to perform adequately. Usually patients are instructed to drink a large amount a fluids prior to the test. Sometimes the bladder is not sufficiently well distended for the test and thus the patient is asked to drink fluids and return later for the test. A transvaginal exam requires an empty bladder.