Radiobiology > In Utero Exposure > Introduction

In Utero Radiation Exposure

Embryos and fetuses are the most radio-responsive life-stages of an organism because of the high rate of mitotic activity. Likewise, any modifications to somatic DNA will distribute among a large number of descendent cells.

Yet in a given population receiving no excess radiation exposure the congenital malformation rate is still 5-6%.  Thus, there is a relatively high rate of spontaneous (background or "natural") genetic change leading to malformation.

Radiation risks to the fetus:

  • Fetal demise
  • Congenital malformation
  • CNS/cognitive effects
  • Carcinogenesis
  • Intrauterine growth retardation

The risk of any one such potential bad outcome varies with gestational age at time of exposure (first trimester > second > third).

Maternal radiation should always be weighed judiciously.  

  • The ACR recommends obtaining informed consent for risk of radiation as well as contrast, if used.   
  • Discuss need for study during pregnancy with referring physician. 
  • Consider whether any suitable diagnostic alternatives are available.
  • Document the above process.


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