Ultrasound Is 'The Best Way to Terrify a Pregnant Woman,' Says One Expert

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Jan. 10, 2000 (Boston) -- Pregnancy ultrasound is a valuable tool for evaluation of the fetus, but its use may lead to emotional distress for women at low risk of having a child with Down's syndrome. That's what Roy A. Filly, MD, writes in a guest editorial subtitled "The Best Way to Terrify a Pregnant Woman" in the current Journal of Ultrasound Medicine. The test, Filly tells WebMD, was originally used to search for abnormal findings in women at high risk for having a child with Down's syndrome, such as being over the age of 35. But the findings are now used to identify Down's syndrome markers in women at low risk, he says. Filly is professor of radiology and of obstetrics/gynecology and reproductive sciences at the University of California, San Francisco.

"I think there's a lot of truth in [Filly's editorial]," Laurence E. Shields, MD, tells WebMD. Shields is an associate professor of perinatal medicine at the University of Washington School of Medicine, in Seattle. "The points he's bringing up are reasonable. Ultrasound technology has improved and people have identified a number of findings they refer to as soft findings of ... abnormal chromosomes [abnormalities that are only rarely associated with problems]. It's a tough thing to decide what to do with that." Shields was not involved in the study.

Filly's goal in raising these issues is to stimulate the relevant professional organizations to decree "it is not appropriate to mention these [ultrasound findings, or markers,] to a woman," he tells WebMD. But "I doubt that you are going to be able to find an organization to do that." Shields, who thinks Filly mildly overstates the case, says that a consensus statement on how to handle such findings would be in order.

The issue that Filly raises has been broached numerous times with respect to screening tests in general. The question is, do screening tests do more harm than good, either by needlessly scaring patients with positive findings that turn out not to be true and/or by precipitating a series of diagnostic tests that may be costly. "For the tiny residual number of Down's syndrome fetuses that may potentially come to light by chasing down every last 'marker' we intend to put at least 10% of all pregnant women with perfectly normal fetuses through a great deal of worry," Filly writes.

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"I have no instance in my recollection where one or the other of these abnormalities was the sole reason I was able to recognize a fetus with Down's syndrome in a low risk patient," Filly writes. "Obviously someone has had such an experience, just not me."

Filly, who performed his first ultrasound on a pregnant woman 30 years ago, suggests that most parents may be incapable of comprehending the minuscule nature of these risks well enough to be relieved of their fears, he tells WebMD.

Asked about peoples' ability to comprehend the nature of such risks, and doctors' ability to explain them, Shields says that at the medical center where he works, "the patient is referred to one of the perinatal centers, and seen by a specialist, and can have a follow-up consultation within 24 to 48 hours. ... When there's any doubt as to what's going on, the person should probably be referred to someone who can explain." But he adds that many doctors "have a difficult time saying, 'I really don't know what this means, let's send you to someone who does.'"

Echoing Filly, Shields says that fear of malpractice contributes to driving doctors to tell patients about soft abnormalities. "Misdiagnosis on ultrasound is becoming one of the new [medical-legal] bonanzas. If you state that [the abnormality] is there, you eliminate your risk."

"It is time," Filly writes, "for the American Institute of Ultrasound in Medicine or the American College of Obstetricians and Gynecologists to convene a panel of experts to analyze the data on this issue and publish a position paper on the practicality of employing the Down's syndrome 'markers' in low risk women at the soonest possible date."

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