What's an Ultrasound?

For many expectant parents, ultrasounds offer a window into the world of their growing unborn baby. Unlike most standard prenatal tests that involve nothing more than a urine cup or a needle, ultrasounds allow a sneak preview of what's to come and what's going on inside — if the heart is beating normally or if the baby registry should contain pink or blue items.

But it's important to remember that ultrasounds are medical procedures that should be done on a health care provider's order. Yet this test that was once used solely by medical professionals is now being utilized by businesses in strip malls and shopping centers to sell keepsake prenatal portraits and videos.

Using technology that allows parents to see high-resolution three- and four-dimensional (moving) images of their babies in the womb, these facilities may employ poorly trained — or even untrained — technicians who aren't given a health provider's order to authorize the procedure and aren't supervised by a physician.

The U.S. Food and Drug Administration (FDA) and the American Institute of Ultrasound in Medicine (AIUM) warn parents-to-be that these nonmedical ultrasounds are unapproved, inappropriate, and possibly even risky.

How It Works

A common diagnostic procedure, an ultrasound uses high-frequency sound waves to "echo," or bounce, off the body and create a picture.

A special jelly is applied to the skin on the expectant mother's abdomen, and a wand-like instrument (called a transducer) is positioned over it. Sound waves are generated and reflected back to the transducer as electric impulses, which produce an image of the baby on a computer screen.

Images seen on most two-dimensional ultrasounds are difficult for the untrained eye to understand. What might look like a hand to an expectant parent might actually be a foot — which is why the images must be interpreted by a properly trained technician. A doctor will then view the report and make his or her own interpretations.

When used correctly — at low power levels and for short periods of time by trained professionals (such as sonographers, radiologists, and obstetricians) — ultrasounds are a standard procedure used to:

• diagnose a pregnancy
• determine multiple pregnancies
• verify the age of the fetus
• detect birth defects and fetal movement
• evaluate the position of the placenta
• monitor the fetal growth and heartbeat

Usually performed between 18 and 20 weeks, an ultrasound can be done sooner or later and sometimes more than once.

Risks of Nonmedical Ultrasounds

Although it might seem harmless to get an extra ultrasound or two, the long-term effects of repeated ultrasounds on a fetus are still unknown. And facilities offering ultrasounds for the purpose of selling videos or portraits — or finding out the baby's gender — might employ poorly trained or untrained technicians who use high power levels for longer periods of time than is deemed safe.

Also, women getting ultrasounds without a health care provider's order might expect to hear that that there are no deformities or complications — a diagnosis that an untrained technician cannot make.

The FDA is also concerned that these nonmedical ultrasounds can be misinterpreted as medical examinations and so prevent women from seeking standard prenatal care.

It might be tempting to get your baby's first portrait before the little bundle of joy is even born, but talk to your OB, nurse-midwife, or family doctor if you're expecting and have questions about ultrasounds. If you've already had a nonmedical ultrasound, be sure to follow up with your health care provider.

Reviewed by: Steven Dowshen, MD
Date reviewed: October 2010