Answer to Question #2988 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation — Conception after exposures

The following question was answered by an expert in the appropriate field:

My husband and I have been trying for four months to have a baby. I don't know if I am currently pregnant or not this month. However, about seven weeks ago, I had an abdominal and pelvic CT scan and a week ago, I had two dental x rays with a shield. I was told that if any cells were damaged from the radiation, they would "die" in a few weeks and couldn't possibly affect future attempts of conceiving a healthy baby. I am very concerned about this situation and I can't seem to get a straight answer from anyone. They just tell me that as long as you are not pregnant, you couldn't possibly cause any harm to the unborn child, which apparently is not the case.

You are concerned about the risk of radiation to your ovaries prior to conception. First of all, there is practically speaking, no radiation exposure to your ovaries form dental x rays. The CT scan probably did expose your ovaries. Depending on the study your ovaries could have received as little as 2 rad to as much as 8 rad. It would be different if you were pregnant at the time of the exposure, but you were not pregnant.

The most important characteristic of x rays that concerns us is the dose. You may not know that we ourselves are radioactive and we are exposed to many sources of natural radiation that we cannot avoid. The data from the atomic bomb survivors who received much higher exposures indicates that the genetic risks from radiation directly to the ovaries are very small. Studies of cancer survivors from studies performed by the National Cancer Institute also indicate that reproductive risks are barely increased even in women who were treated with chemotherapy and radiation to the ovaries. And remember, you had a very low dose of radiation to your ovaries.

I could provide you with the theoretical risks, but you did not give me the estimated exposure of the CT scan. Even if I use the highest possible exposure, your risks are so small that they are dwarfed by the background incidence of reproductive risks.Therefore your genetic risks are extremely small.

If you are healthy, and have no reproductive problems or family history of reproductive problems your risk for birth defects is 3% and for miscarriage, 15%. Neither you nor I can change that risk which all mothers have when they begin a pregnancy. Good luck with your pregnancy.

Robert L. Brent, MD, PhD

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