Many expectant parents look forward to prenatal appointments that include an ultrasound. Ultrasound technology gives parents a preview of what their unborn child looks like, and can provide assurance that their child is healthy. Ultrasounds can also be used to detect fetal abnormalities early in pregnancy. Although ultrasounds are non-invasive, parents sometimes question whether the benefits outweigh the risks.
How Ultrasounds Work
Ultrasounds are a type of sonar technology, meaning they uses high-frequency sound waves to form a picture of an object--or in the case of prenatal ultrasound, a picture of the fetus. A wand, called a transducer, is placed on the abdomen. The transducer sends and receives sound waves, and when the sound wave reaches an object, it bounces back. The pattern of returning sound waves produces an image, which is the image you see on the screen of the ultrasound machine.
History
The precursor to ultrasound technology is the development of sonar technology, which began in the mid-1800s. Over time, scientists discovered that sound waves could form images when bounced directly toward an object. Doctors began exploring its medical applications in the 1930s. They initially attempted to use ultrasounds to treat diseases, with little efficacy. In the early 1950s doctors began to use ultrasounds diagnostically to image tumors and abscesses. By the early 1960s, ultrasounds were being used to diagnose fetal abnormalities.
Benefits
Prenatal ultrasounds have a number of benefits, the majority of which involve detecting fetal abnormalities. Many women in the United States are given a first trimester ultrasound, which can screen for genetic abnormalities such as Down syndrome and Trisomy 18. These early results can give women information needed in deciding whether to terminate their pregnancy due to poor fetal health. Later in pregnancy, ultrasounds can be used to monitor fetal growth and development, umbilical blood flow and placement of the placenta. All of these are important in determining whether early induction or a scheduled cesarean section are medically necessary.
Risks
While ultrasounds have been used prenatally for over 50 years with no obvious ill effects, there are still certain health concerns. In 1991, federal regulations concerning ultrasounds were relaxed, allowing for more intense high-frequency sound to be used. Some worry that there is a lack of research concerning these higher-frequency waves, though no immediate consequences have been observed. Also, ultrasound waves produce a certain amount of heat, which has the potential to be harmful to a fetus. However, trained ultrasound technicians are aware of this risk and minimize it by never leaving the transducer in one place for too long.
3-D Ultrasounds
A new concern parents have is the trend toward elective 3-D ultrasounds. Parents usually pay out of pocket for these ultrasounds, as they are not medically indicated. Three-dimensional ultrasounds provide an image that is much more lifelike than their diagnostic 2-D counterparts. While no immediate negative effects have been observed, federal organizations do not condone the use of ultrasound technology for nonmedical uses. Additionally, as 3-D ultrasound is a relatively new technology, there is no way to determine any long-term side effects.
