The past decade has seen an unprecedented increase in the use of radiologic exams on pregnant women, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).
“Through medical imaging examinations, we are exposing pregnant women to twice the amount of radiation as we did 10 years ago,” said Elizabeth Lazarus, M.D., assistant professor of diagnostic imaging at the Warren Alpert School of Medicine at Brown University in Providence, R.I. “Overall, the levels of radiation to which we are exposing pregnant women are low, but they do carry a slight risk of harm to the developing fetus.”
The researchers conducted a retrospective review of selected imaging examinations – nuclear medicine, computed tomography (CT) and plain-film x-rays – performed at Brown to determine how often these imaging exams were utilized in pregnant women and the estimated resulting radiation dose to the fetus. Data were compiled for the years 1997 through 2006 and compared to the number of infant deliveries per year.
The investigators found that from 1997 to 2006, the number of imaging studies performed on pregnant women increased by 121 percent. The greatest increases were in the number of CT exams, which deliver more radiation than many other radiologic procedures. An abdominal CT exposes the patient to a radiation amount more than twice that of an x-ray of the lower gastrointestinal tract. An abdominal ultrasound exposes the patient to no ionizing radiation.
CT is not routinely used in pregnancy, but pregnant women may undergo CT to detect suspected life-threatening conditions such as bleeding in the brain, blood clots in the lungs or appendicitis. Since CT exposes the developing fetus to radiation, concerns are often raised regarding overuse. The majority of CT examinations (approximately 75 percent) analyzed in the study were performed in areas of the mother's body separate from the uterus, so the fetus was not exposed to any direct radiation. Even low levels of radiation have been shown to carry a small risk of harm to a developing fetus.
“While performing CT exams during pregnancy is still uncommon, we found that pregnant women are being recommended for CT more often over the last 10 years,” Dr. Lazarus said.