Obstetrical Ultrasound

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Obstetrical (OB) ultrasound exams are used to check the condition of a pregnant women and her unborn baby.

Ultrasound imaging is used during pregnancy to obtain pictures of internal organs by sending and receiving sound waves into the body. The sound waves are recorded and displayed on a screen. X-rays are not used in ultrasound. OB ultrasound is the special use of sound waves to check the health of a pregnant woman and her unborn baby.

Ultrasound sends sound waves into the body using a transducer, a hand-held device that sends and receives sound waves. After gel is applied to the skin, the sonographer will press the device against the skin to obtain pictures, which then appear on a screen. As the sound waves echo from the fluids and tissues, a picture is formed in real-time showing both the mother’s and the baby’s tissues.

• If an ultrasound is done before 18 weeks of pregnancy, you need to have a full bladder for the exam. The full bladder allows a better view of the baby and organs. You should drink a quart of water one hour before the exam so your bladder will be full.
• The sonographer (technologist) or radiologist may elect to image an early pregnancy with transvaginal ultrasound (a small transducer placed in the vagina) in addition to the abdominal approach. This is done with an empty bladder, so you will need to empty your bladder at that time.
• You should wear a loose-fitting, two-piece outfit for the exam. Only the lower abdominal area needs to be exposed during the exam.

1. You will lie on an exam table, and your clothing is moved away from the lower abdominal area.
2. Warm gel is applied to the abdomen to make contact between your skin and the transducer.
3. The sonographer then presses the device against your skin and sweeps it over the abdomen to obtain pictures.
4. The radiologist may obtain more pictures after the sonographer is done.

• Ultrasound of the abdomen is fast, painless, and easy.
• You will feel the sonographer apply warm gel to your abdomen, and press the transducer against your skin. The transducer will be moved over your skin until all of the pictures are taken.
• You may be asked to roll on either side, or change positions.
• There is little or no discomfort with the procedure.
• The exam usually takes less than 1 hour for a single baby, and up to 2 to 3 hours for twins and triplets.

The radiologist who specializes in ultrasound will review the pictures and send a report to your referring doctor. You will receive your results from the doctor who ordered the test. In some cases, the radiologist may discuss early findings with you when your exam is over.