As you lie on an exam table, a sonographer coats your belly with a slick -- and possibly cold -- gel. Next, he moves a transducer, a hand-held device shaped like a microphone, over your belly. You can see the resulting images on a nearby computer screen.
Update Date 4/5/2016
Updated by: Irina Burd, MD, PhD, Associate Professor of Gynecology and Obstetrics at Johns Hopkins University School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.