THE MEDICAL IMAGING EXPERIENCE
INFORMATION FOR THE PATIENT
OBSTETRIC ULTRASOUND

WHAT IS IT?
Ultrasound procedures involve the use of very high frequency sound waves. The actual sound cannot be heard with the human ear. The sound waves are sent into the body using a hand held instrument called a transducer. This ultrasound device will not harm your baby. The various structures of your baby such as the stomach, liver and kidneys are evaluated to make sure everything is normal. Measurements are taken to evaluate the size of different body parts and to determine the approximate age and delivery date of your baby. The various structures in the baby including organs, tissue and fluids (such as blood and water) reflect sound waves differently because of their different density. Some of the sound waves reflect back to the transducer much like your voice echoes back to you in an empty building. The reflected sound waves are received by the transducer and sent to a computer to be processed into pictures.

WHAT WILL HAPPEN TO ME?
The sonographer (the person who operates the ultrasound machine) will assist you as you lie on your back on a padded table. A warm gel will be spread on your abdomen. The gel improves the ability to send and receive the sound waves between the transducer and your body. The sonographer moves the transducer over your abdomen while frequently changing the position and angle of the transducer. This action guides the sound waves to specific parts of the body so that pictures can be taken. The sonographer may ask you to change positions or hold your breath for short periods of time.

Sometimes the physician who will interpret the ultrasound procedure will also operate the transducer.

HOW LONG WILL THIS TEST TAKE?
This ultrasound procedure usually takes 45 - 60 minutes to complete.

WHAT WILL I FEEL -- WILL IT HURT?
Usually the ultrasound room lights are turned down to darken the room. This helps the sonographer to see the video screen better. Ultrasound procedures are not painful. You will feel some pressure as the sonographer presses the transducer against your abdomen.

WHAT WILL THE TEST SHOW?
Ultrasound us used to look at the shape, size and position of various anatomical features of your baby. Ultrasound is used to determine the age, weight and delivery date of your baby. Ultrasound can be used to determine the sex of your baby after about 18 weeks. Ultrasound is also used to determine your baby's position and the location of the placenta which is important to know before your delivery.

HOW DO I GET READY?
A full bladder is needed for this exam during the first and second trimester of your pregnancy.

Reviewed: September 2005