According to recent study, pregnant woman are exposing their unborn children to high doses of radiation by receiving high-tech imaging exams. This exposure is higher than those reported ten years ago. The study reviewed examinations on more than 5,235 pregnant women from 1997 to 2006. Researchers also found that women the number of CT and X-rays increased 121 percent.

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

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

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

Researchers estimated 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. The data were released at a meeting of the Radiological Society of North America in Chicago.

"A patient being recommended for a test like this should talk to their doctor to find out if there are any alternative tests or if there is any harm waiting," Lazarus said in an interview.

"But if one of these tests is needed, we would not discourage any patients from undergoing one, because making a diagnosis could also be life-saving."