McKesson Clinical Reference Systems: Women's Health Advisor 2002.2
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Why is ultrasound used?

Ultrasound uses sound waves to make a picture of your baby inside your uterus. Your health care provider can also use it to look at your uterus, amniotic sac, placenta, and ovaries. You may be able to find out if your baby is a boy or a girl, but that is not usually the reason for having an ultrasound.

Ultrasound can help your health care provider:

• Find out how far along you are in the pregnancy.
• Check the baby's growth.
• Figure out how much the baby weighs.
• Measure the baby's bones, head, and abdomen.
• Check the baby's heart.
• Look for movement by the baby.

It can also help your health care provider check for problems. For example, he or she can:

• Make sure the baby is growing inside the uterus.
• Check for more than one baby.
• See if the placenta is normal and attached to the uterus the right way.
• Check how the baby is lying in the uterus.
• Make sure there are no problems with your uterus.

What happens during the ultrasound?

Your health care provider may want you to have a full bladder when the ultrasound is done. He or she may tell you:

• Drink about 6 glasses of water an hour before the ultrasound.
• Do not urinate the hour before your ultrasound.

An ultrasound takes about 15 minutes. It does not hurt you or your baby.

The person who does the ultrasound may be your health care provider or a technologist. He or she will:

• First put a gel on the skin of your abdomen.
• Then move a wand, called a transducer, slowly over your abdomen.

The wand sends and picks up sound waves. It then makes a picture on the screen. You can see the picture as the wand moves over your belly. It can be hard to tell what you are seeing. Your health care provider can help explain what parts of the baby you are seeing.

Sometimes ultrasound is done through the vagina, especially early in a pregnancy. Then it is done with a wand shaped like a narrow tube.

Talk to your health care provider if you have questions about having an ultrasound, or what it shows.

This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.