What dose metric is used to protect the unborn child of a declared pregnant worker, and what is the total dose limit?

• A. Fetal dose; limit is 1 rem (10 mSv) for the entire pregnancy.
• B. Embryo dose; limit is 0.05 rem (0.5 mSv) per month.
• C. Embryo dose; limit is 0.5 rem (5 mSv) for the entire pregnancy.
• D. Embryo/fetus dose; limit is 0.5 rem (5 mSv) for the entire pregnancy.

Answer: (C)

Protecting the developing child uses a fetal or embryonic dose concept, which tracks the radiation dose that the embryo or fetus would receive. The important point is that this dose is a cumulative limit for the entire pregnancy, not a monthly or single-incident cap. For a declared pregnant worker, the standard limit is 0.5 rem (5 mSv) for the whole pregnancy. This conservative limit helps protect the most sensitive stages of development from deterministic effects and minimizes long-term risk.

The other options don’t fit as well because they either use a different dose metric, or they apply a monthly or higher limit that doesn’t reflect the pregnancy-wide cap.