What is the purpose of having a full bladder prior to a pelvic ultrasound?
Ultrasound cannot see through air or gas. We use a full bladder to push the intestines (which contain gas) up and away from the uterus and ovaries. Ultrasound travels well through fluid, so the sound waves travel through the urine filled bladder and provide a good “window” which we can use to view the uterus and ovaries. The full bladder pushes the uterus out of the bony pelvis. Ultrasound cannot see through bones. Make sure you empty your bladder prior to drinking your water. You want to start with an empty bladder, so you don’t overfill and become extremely uncomfortable. If you feel like you have to go to the bathroom, and you are somewhat uncomfortable, but not about to pee your pants, you have enough in your bladder to image the uterus and ovaries well! You will do fine, and it will be over quickly. If they need to do a transvaginal ultrasound, you will be asked to completely empty your bladder! A fluid filled bladder will interfere with transvaginal pelvic imaging!
