Ultrasound is a useful procedure for monitoring the baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two-dimensional image of the baby while inside the mother's uterus. The sound waves bounce off solid structures in the body and are transformed into an image on a monitor screen.
Solid structures, such as bones and muscles, reflect sound waves and appear as light gray or white. Soft or hollow areas, like the chambers of the heart, don't reflect sound waves and appear dark or black.
An ultrasound can supply vital information about a mother's pregnancy and her baby's health. Even though there are no known risks for ultrasound at present, it is highly recommended that pregnant women consult their physician before undergoing this procedure.
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.