Radiation exposure to pregnant women from diagnostic procedures will almost never result in fetal-absorbed doses that are high enough to cause damage to the fetus unless multiple examinations are performed. Prenatal radionuclide dose or technical factors of X-ray exposure should be recorded to facilitate estimation of fetal dose. Fetal doses of less than 100 mGy (10 rad) do not increase the incidence of fetal malformation. Doses of 200 to 500 mGy (20 to 50 rad) should be evaluated in the context of the type of radiation and time of exposure relative to fetal development and may be associated with a reduction in IQ. Radiation doses greater than 500 mGy (50 rad) result in a significant risk of growth retardation and CNS damage.