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24 May 2012

Answer to Question #1167 Submitted to "Ask the Experts"

Category: Pregnancy and Radiation — Radiation effects to embryo/fetus

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

Why is the embryo most vulnerable to ionizing radiation between one and three months?

The embryo (stage of pregnancy up to about six weeks post conception) and the fetus (the stage of pregnancy from six weeks onward) will be most sensitive to exposure to ionizing radiation exposure when the cells are dividing rapidly and are the least specialized. These factors are at play during the first three months of pregnancy. In addition, it is during this time that the organs are being formed. Injury to a few cells at this stage poses more of a risk than injury at a later stage. Detailed information on prenatal radiation exposures can be found on the US Nuclear Regulatory Commission website under Regulatory Guide 8.13.

Genevieve S. Roessler, PhD

Answer posted on 19 September 2001. The information and material posted on this website is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of 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 specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Website. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.