Radiation and pregnancy

Irradiation of pregnant women either in the workplace or as a consequence of clinical diagnosis is often unavoidable. This paper reviews the issues relating to this topic. For clinical exposures the "missed period" rule is applied prior to most clinical studies. However normal physiological variations in the menstrual cycle may need to be understood. The possible effects of irradiation, both deterministic and stochastic, on the fetus are also described. The decision process in relation to irradiation of a pregnant or potentially pregnant patient is discussed in terms of the regulatory guidance. A different approach is needed for studies which clearly involve a low dose to the uterus compared with studies involving a high dose, including therapy. The issue of a pregnant or potentially pregnant worker in nuclear medicine is also considered. Restrictions on certain work activities may be necessary once pregnancy is declared. Other areas considered are biomedical research and also the potential for exposure of pregnant woman in the home or in the workplace as a consequence of others having a nuclear medicine study.