Pregnant women may be having too many high-tech scans

Nov 27 2007

A new study has found that pregnant women are having more high-tech imaging examinations and are thereby exposing their babies to higher doses of radiation than a decade ago.

According to the scientists even though the levels of radiation exposure are low, computed tomography (CT), nuclear medicine and X-rays do nevertheless carry a slight risk of harm to the developing fetus.

Study author Elizabeth Lazarus, a professor of diagnostic imaging at the Warren Alpert School of Medicine at Brown University in Providence, Rhode Island, reviewed 5,235 imaging examinations performed on pregnant women at Brown from 1997 to 2006 and found the number of those exams rose 121 percent.

The examinations included CT scans, nuclear medicine scans and plain-film X-rays.

The researchers have estimated that the average fetal radiation exposure for CT was 0.69 rads, compared to 0.04 rads for nuclear tests and 0.0015 rads for X-rays.

CT exams, which deliver more radiation than other procedures, saw the greatest increase in use, rising by about 25 percent a year, nuclear medical exams rose by 12 percent and the use of X-rays increased by 7 percent a year.

As a rule CT scans are only used in pregnancy to detect potentially life-threatening conditions such as bleeding in the brain, blood clots in the lungs or appendicitis.

An abdominal ultrasound, a routine exam performed during pregnancy, does not expose the patient to ionizing radiation, which can cause cell damage.

Dr. Lazarus says pregnant women advised to have such tests should discuss alternatives with their doctor or find out if there is any harm in waiting.

Dr. Lazarus however also says if one of these tests is needed a pregnant woman should not be discouraged by the study because making a diagnosis could also be life-saving.

Other studies have also shown that the use of CT and magnetic resonance imaging (MRI) has increased in all patient populations throughout the United States.

Dr. Lazarus suggests this increase is partly due to the development of new imaging techniques to better diagnose abnormalities, but some is due to motivation by hospitals and insurers to make fast diagnoses in order to shorten hospital stays and improve patient care.

The study was presented at a meeting of the Radiological Society of North America in Chicago.