How To Prepare
You may need a full bladder for the test. If so, you will be asked to drink water or other liquids just before the test and to avoid urinating before or during the test. Usually women in the third trimester do not need to have a full bladder.
For a transvaginal fetal ultrasound, the vaginal transducer is usually covered with a latex sleeve and a vaginal lubricant, such as K-Y Jelly. If you are allergic to latex, tell the health professional before having the test.
Talk to your doctor about any concerns you have regarding the need for the fetal ultrasound, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).
How It Is Done
Most often, a fetal ultrasound is performed by an ultrasound technologist. But it may be done by a radiologist or obstetrician. Fetal ultrasound can be done in a doctor's office, hospital, or clinic.
Often you do not need to remove your clothes for the ultrasound test. You can lift your shirt and push down the waistband of your skirt or pants. If you are wearing a dress, you will be given a cloth or paper covering to use during the test.
- You may need to have a full bladder . A full bladder helps transmit sound waves and pushes the intestines out of the way of the uterus. This makes the ultrasound picture clearer.
- You will not be able to urinate until the test is over. But tell the ultrasound technologist if your bladder is so full that you are in pain.
- If an ultrasound is done during the later part of pregnancy, a full bladder may not be needed. The growing fetus will push the intestines out of the way.
- You will lie on your back on a padded examination table. If you become short of breath or lightheaded while lying on your back, your upper body may be raised or you may be turned on your side.
- A gel will be spread on your belly.
- A small, handheld instrument called a transducer will be pressed against the gel on your skin and moved across your belly several times. You may watch the monitor to see the picture of the fetus during the test.