Fetal Ultrasound: How It Is Done

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How It Is Done

Most often, a fetal ultrasound is performed by an ultrasound technologist. However, it may be done by a radiologist or obstetrician. Fetal ultrasound can be done in a doctor's office, hospital, or clinic.

See a picture of how a fetal ultrasound is done .

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.

Transabdominal ultrasound

• You will 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. However, tell the ultrasound technologist if your bladder is so full that you are in pain.
  • If you cannot drink enough liquid, your bladder may be filled with sterile water through a thin flexible tube (urinary catheter) inserted through your urethra.
  • 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.

When the test is finished, the gel is cleaned off of your skin. You can urinate as soon as the test is done. Transabdominal ultrasound takes about 30 to 60 minutes.

Ultrasound technologists are trained to gather images of your fetus but cannot tell you whether it looks normal or not. Your health professional will share this information with you after the ultrasound images have been reviewed by a radiologist or perinatologist.

Transvaginal ultrasound

• You do not need to have a full bladder.
• You will lie on your back with your hips slightly raised.
• A cover (such as a condom) will be placed over the thin vaginal transducer. The transducer will be inserted gently into your vagina, and then it will be moved and rotated to adjust the view displayed on the monitor. Some doctors may allow you to insert the transducer into your vagina yourself.

Transvaginal ultrasound takes about 15 to 30 minutes.

Last updated:	June 28, 2007
Author:	Maria G. Essig, MS, ELS
Reviewed By:	Joy Melnikow, MD, MPH - Family Medicine, Deborah A. Penava, BA, MD, FRCSC, MPH - Obstetrics and Gynecology
Editors:	Susan Van Houten, RN, BSN, MBA, Tracy Landauer