For a declared pregnant female, what is the embryo dose limit?

• A. 500 mrem
• B. 50 mrem
• C. 5 rem
• D. 1000 mrem

Answer: (A)

Protecting the developing fetus from ionizing radiation is the focus. When pregnancy is declared, the dose to the embryo/fetus is limited to 0.5 rem for the entire pregnancy (500 mrem or 5 mSv). This limit is cumulative from the time the pregnancy is declared until delivery, regardless of how the exposure is delivered, and it is more restrictive than the usual occupational limit for workers. In practice, safeguards like shielding, reduced exposure time, task adjustments, and fetal dosimetry help ensure the limit isn’t exceeded. The other numbers either exceed this fetal limit or refer to the general annual occupational dose, which is why they don’t apply to the embryo during pregnancy.