Prenatal Radiation Exposure: Background Material for Counseling Pregnant Patients Following Exposure to Radiation

¹ Ms Donnelly and Dr Smith are with the Centers for Disease Control and Prevention. Dr Farfan is with the Savannah River National Laboratory-Environmental Science and Biotechnology. Mr Ozcan is with the Lawrence Berkeley National Laboratory.

^* To whom correspondence should be addressed. E-mail: edonnelly{at}cdc.gov.

Abstract

Fetal sensitivity to radiation-induced health effects is related to gestational age, and it is highly dependent on fetal dose. Typical fetal doses from diagnostic radiology are usually below any level of concern. Although rare, significant fetal radiation doses can result from interventional medical exposures (fluoroscopically guided techniques), radiation therapy, or radiological or nuclear incidents, including terrorism. The potential health effects from these large radiation doses (possibly large enough to result in acute radiation syndrome in the expectant mother) include growth retardation, malformations, impaired brain function, and neoplasia. If exposure occurs during blastogenesis (and the embryo survives), there is a low risk for congenital abnormalities. (In all stages of gestation, radiation-induced noncancer health effects have not been reported for fetal doses below about 0.05 Gy [5 rad].) The additional risk for childhood cancer from prenatal radiation exposure is about 12% per Gy (0.12%/rad) above the background incidence.

Key Words: prenatal radiation exposure, radiation health effects, radiological emergencies, fetal radiation dose, tutorial