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Health & Pregnancy

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Prenatal Ultrasound

What Is a 3-D and 4-D Ultrasound?

Newer ultrasounds are now available that show a three-dimensional view of the fetus. This is similar in clarity to a photograph and can be useful in detecting birth defects when performed in a medical center. Some facilities are providing this scan at the parents' request without a specific medical indication. A moving picture interpretation is referred to as a 4-D ultrasound. According to the March of Dimes, the FDA, and other experts, the use of these non-medical ultrasounds is discouraged, because untrained personnel may provide inaccurate or harmful information.

How Should I Prepare for an Ultrasound?

There is no special preparation for the ultrasound test. Some doctors require you to drink 4-6 glasses of water before the test, so your bladder is full. This will help the doctor view the baby better on the ultrasound. You will be asked to refrain from urinating until after the test.

Some doctors allow you to videotape the ultrasound so that you can take it home. Ask your doctor if this is an option. If it is, you will need to bring a blank videotape or DVD to your appointment.

What Happens During an Ultrasound?

You may be asked to change into a hospital gown.

You will lie on a padded examining table during the test and a small amount of water-soluble gel is applied to the skin over your abdomen. The gel does not harm your skin or stain your clothes.

A small device, called a transducer, is gently applied against the skin on your abdomen. The transducer sends high-frequency sound waves into the body, which reflect off internal structures, including your baby. The sound waves or echoes that reflect back are received by the transducer and transformed into a picture on a screen. These pictures can be printed out or sometimes recorded on a videotape.

There is virtually no discomfort during the test. If a full bladder is required for the test, you may feel some discomfort when the probe is applied over the bladder.

You may be asked to hold your breath briefly several times.

The ultrasound test takes about 30 minutes to complete.

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