Ultrasound Affects Fetal Brain in Mice
Impact on Humans Unknown; Mouse Effect Seen After 30-Minute Exposures
Findings Need Confirmation continued...
The research did not show the change resulted in behavioral differences in the mice after birth, but the findings were of concern, study co-author Pasko Rakic, MD, PhD, tells WebMD.
"Clearly, we have to confirm these findings by looking to see if they occur in larger animals," he says.
The Yale researchers have begun just such a study in monkeys. Rakic says the results will not be known for several years.
"Our study in mice does not mean that use of ultrasound on human fetuses for appropriate diagnostic and medical purposes should be abandoned," he says, adding the benefits of medically indicated fetal ultrasounds clearly outweigh potential risks.
But he agrees pregnant women should avoid having ultrasounds that aren't medically indicated.
Entertainment ultrasounds could turn out to be this generation's equivalent of X-raying feet to determine shoe size, Rakic says. That practice was common in the late 1940s and early 1950s, and most shoe stores had their own X-ray machines.
"We now know that X-rays can be dangerous, and that exposures should be limited to only those that are medically necessary," he says.
Joshua A. Kopel, MD, a professor of obstetrics, gynecology, and reproductive sciences at Yale, says there is no indication the widespread use of fetal ultrasound over the last three decades has influenced brain development.
"There is no evidence that our children are dumber than we are. If anything, studies suggest that they are smarter," Kopel says. "But any time an ultrasound is used there ought to be a medical question being answered."