What is a safeguard to prevent accidental exposure of a pregnant woman to radiation?

The most effective safeguard to prevent accidental exposure of a pregnant woman to radiation is to post signs of caution in waiting rooms. By providing visible warnings about the risks associated with radiation exposure for pregnant women, healthcare facilities can increase awareness among patients and staff. This proactive approach ensures that everyone is informed and can take appropriate steps to minimize potential risks, such as alerting healthcare providers about their pregnancy status before any imaging procedures occur.

The other options, while they may contribute to safety in some aspects, do not address the specific need to safeguard pregnant women from radiation exposure in a direct manner. For example, restricting access to radiology departments might prevent potential exposures, but it doesn't ensure that individuals are informed of their exposure risks. Similarly, limiting examinations to emergency cases could reduce frequency but doesn't eliminate risk entirely and could deny necessary care. Lastly, only allowing males for procedures is an extreme and impractical measure that does not consider the healthcare needs of all individuals and fails to address informed consent and awareness about risks.