Fetal risk in diagnostic radiology.

It is not uncommon to encounter situations in which radiologic examinations are necessary for accurate diagnosis and effective treatment of an expectant mother. The potential deleterious health consequences to the developing embryo and fetus from in utero irradiation include fetal death, congenital malformations, growth retardation, and carcinogenic and mutagenic effects. The likelihood of each effect is greatly dependent on the radiation dose and the gestational age of the conceptus at the time of exposure. In general, the average fetal doses from diagnostic imaging are <50 mGy (5 rad) and have not been associated with any significant adverse fetal effects. However, each case should be evaluated on an individual basis, and the risks should be explained to the patient before the examination. In addition, every effort should be made to reduce the fetal dose to as low as reasonably achievable. The biological effects of in utero radiation exposure, estimated fetal doses from various radiologic examinations, and general guidelines regarding diagnostic imaging during pregnancy will be discussed in this article.