U.S. Nuclear Regulatory Commission
Question 120: Would a licensee be found to be in noncompliance with the limit for the dose to an embryo / fetus if, at the time the woman declared her pregnancy, the dose to the embryo / fetus exceeded 0.5 rem and the embryo / fetus subsequently received more than 0.05 rem from licensed material that was in the body of the woman before she declared her pregnancy.
Answer: No. The intent of 10 CFR 20.1208 (d) is that the licensee should not be in violation of the limit for the embryo / fetus as a result of doses received by the embryo / fetus before the woman declared her pregnancy or doses received as a result of intakes before that declaration was made.
(Reference: 10 CFR 20.1208)