Answer to Question #7250 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation — Exposures to embryo/fetus

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


I recently had an iodine-123 scan. Two days later I discovered that I was 12 to 14 weeks pregnant. I had no other reason to think that I was pregnant except for some nausea. What are the effects on me and the fetus at this stage of a pregnancy?


You had a diagnostic scan with a low exposure to iodine-123. This would not affect your fetus' thyroid and would not be responsible for increased risk of birth defects or miscarriage. Furthermore at 12 to 14 weeks the fetus has formed all the major organs.

If you are healthy, young, and have no reproductive problems or family history of reproductive or developmental problems, your risk for birth defects is 3% and for miscarriage, 15% (although at your stage miscarriage is much less of a risk). These are background risks with which every woman begins her pregnancy. Neither you nor I can change these risks. Good luck with your pregnancy.

Robert Brent MD, PhD

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 18 February 2008. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.