Pregnant women are exposed to more high-tech imagines exams, exposing their babies to higher level of radiation than a decade ago, a study revealed on Tuesday.

Although the level of radiation is low, developing fetus are still exposed to slight risks according to the author of the study Elizabeth Lazarus, a professor of diagnostic imaging at the Warren Alpert School of Medicine at Brown University in Providence, Rhode Island.

"Through medical imaging examinations, we are exposing pregnant women to twice the amount of radiation as we did 10 years ago. 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," said Lazarus.

The findings were presented at the annual meeting of the Radiological Society of North America on Tuesday.

The study analyzed 5,235 imaging examinations performed on pregnant women at Brown between 1997 and 2006 and found that the number of those exams rose with 121 percent. The exams included computed tomography (CT), nuclear medicine and plain film X-rays. The use of CT scans in particular is on the rise, jumping to 62 million in 2006, from 3 million in 1980, meaning they increased with 25 percent each year.

Abdominal ultrasounds performed during pregnancy do not expose the patient to ionizing radiation, a type of radiation that can alter cells and lead to health risks, including cancer.

CT scans “deliver more radiation than many other radiologic procedures,” the report says.

Lazarus said the increase followed the development of new imaging techniques for diagnosing abnormalities and because hospitals and insurers wanted to make faster diagnosis.

A CT scan shows whether the baby faces bleeding in the brain, blood clots in the lungs or appendicitis.

Doctors should be more circumspect when ordering scans of pregnant women, Lazarus underlined.

“I want to assure patients that CT can be a safe, effective test for pregnant patients. However, there are alternatives that should at least be explored. Pregnant patients should ask their doctors about other imaging or diagnostic tests that may not expose the fetus to radiation.”