Radiation and pregnancy

Irradiation of pregnant women either in the workplace or as a consequence o f clinical diagnosis is often unavoidable. This paper reviews the issues re lating to this topic. For clinical exposures the "missed period" rule is ap plied prior to most clinical studies. However normal physiological variatio ns in the menstrual cycle may need to be understood The possible effects of irradiation, both deterministic and stochastic, on the fetus are also desc ribed. The decision process in relation to irradiation of a pregnant or pot entially pregnant patient is discussed in terms of the regulatory guidance. A different approach is needed for studies which clearly involve a low dos e to the uterus compared with studies involving a high dose, including ther apy. The issue of a pregnant or potentially pregnant worker in nuclear medi cine is also considered. Restrictions on certain work activities may be nec essary once pregnancy is declared. Other areas considered are biomedical research and also the potential for e xposure of pregnant woman in the home or in the workplace as a consequence of others having a nuclear medicine study.