Radiation Scans in Pregnancy Rising

Nov. 27, 2007 (Chicago) -- Pregnant women are being exposed to more than twice the amount of radiation from medical imaging scans than they were a decade ago, potentially placing themselves and their unborn babies at risk of future health woes, researchers report.

Although the average amount of radiation a woman received during any scan was well below the accepted limits for exposure in pregnancy, it's hard to know what the health effects will be decades down the road, says Philip O. Alderson, MD, chairman of radiation oncology at Columbia University in New York.

Exposure to radiation in pregnancy has been shown to place both the mom and her baby at increased risk of cancer; the child may also face learning and developmental problems. The health risks are cumulative; the greater one's exposures throughout a lifetime, the greater the risk.

Alderson, who was not involved with the work, moderated a news conference to discuss the findings at the annual meeting of the Radiological Society of North America.

Rise in CT Scans Drives Trend

For the study, Brown University researchers reviewed 5,235 radiological examinations -- X-rays, nuclear medicine scans, and computed tomography (CT) scans -- performed on 3,249 pregnant women from 1997 to 2006.

Over the 10-year course of the study, the number of women imaged increased 91% and the number of actual examinations performed on pregnant women shot up 125%.

A dramatic 25% rise in CT scans, which deliver more radiation and therefore pose more health risks than other procedures, drove the troubling trend, says Elizabeth Lazarus, MD, assistant professor of diagnostic imaging at the Brown's Warren Alpert School of Medicine.

The use of nuclear medicine scans increased 17% over the 10 years of the study; X-rays rose just 7%.

Ask About Non-Radiation Options

Nearly one-third of the CT scans were of the abdomen or pelvis, "where the fetus is directly in the beam of radiation," Lazarus says.

She tells WebMD that pregnant women who are scheduled for a radiological exam should ask their doctors about alternative tests that do not involve radiation. They may also want to inquire about the danger of putting the test off until after the pregnancy, she adds.

Lazarus says that suspected appendicitis was the most common reason that the pregnant women got an abdominal CT.

Magnetic resonance imaging (MRI) scans can also diagnose appendicitis and do not emit radiation, Lazarus says. However, they are not available at every hospital.

The researchers stress that in many cases, CT scans are appropriate in pregnancy.

"CT scans are making a terrific contribution to the health of our population," Alderson says. "The problem is overutilization."

Why So Many Scans?

So why are pregnant women undergoing so many more scans than in the past? According to Lazarus, some of this increase is due to the development of new imaging techniques that better diagnose health problems.

But doctors, hospitals, and insurers seeking to make accurate yet fast diagnoses are also playing a role, she says. Many practice "defensive medicine in an increasingly litigious environment" in which health care providers fear malpractice suits if they miss a diagnosis, she says.