Answer to Question #1100 Submitted to "Ask the Experts"

Q

I had a noncontrast CT of the abdomen last Friday. They were only supposed to do a kidney CT, not abdomen. I'm 40 1/2 and hope to get pregnant soon. I had a miscarriage three months ago. I'm concerned about the unneeded radiation on my ovaries and uterus. It's upsetting. Here's my question. They did two passes on a GE lightspeed. Do you know how much radiation was absorbed and what damage it might have done? Would it be wise to wait to let possibly genetically damaged/mutated eggs ovulate out before we try to conceive again?

A

My brief answer to your question is that the radiation received in a diagnostic CT study should not play any role in a decision to have children. The fact is that there are no identifiable cases of an individual having been affected adversely by preconception exposure of the parent to radiation. While some studies have reported such effects, other factors have later been shown to be the likely culprits, not the radiation. Even in the population of individuals exposed to the atomic-bomb radiation at Hiroshima and Nagasaki (~70,000 progeny studied), no positively identifiable cases of adversely affected progeny due to radiation exposure have been identified. For a more complete discussion, please refer to Exposure of the Pregnant Patient to Diagnostic Radiations - a Guide to Medical Management, second edition, which was published by Medical Physics Publishing of Madison, Wisconsin, in 1997, pages 88-92. See also Hall EJ: Radiobiology for the Radiologist, fifth edition, which was published by Lippincott Williams & Wilkins in 2000, pages 174-176. The bottom line is that the risk is very low. There are several cases where fathers have been rendered infertile for an extended period by exposure to radiation but later regained their fertility to parent healthy children. In one case a child grew up to become a medical doctor who was a student in my class. While some find it difficult to discuss, the facts are that, in the natural order of reproduction, not all conceptions are destined to result in children without physical, mental, or biological deficiencies. This is irrespective of any radiation exposure. This fact has not deterred us from risking these potential adverse outcomes in favor of the rewards of parenthood. Given that radiation received from a diagnostic CT examination will not measurably change this larger natural-order risk of pregnancy, my attitude is that I should worry more about the natural frequency of unhealthy outcomes and take all precautions to limit these risks. For example, a healthy diet free of alcohol, smoking, and other adverse agents should be encouraged before conception. For medical advice, please consult a knowledgeable physician. Delaying conception after irradiation may have some benefit, but it also has consequences. Studies in laboratory animals suggest that delaying conception for two to six months following irradiation decreases the possibility of an adverse outcome from preconception irradiation. On the other hand, age of the parent is also a risk factor and delaying conception may result in missed opportunities. Since it is so difficult to identify any adverse effects in the human population from preconception irradiation, my opinion is that delaying conception after a CT scan has dubious benefit. Lou Wagner, PhD Medical Physicist