Prenatal X-Ray Exposure and Twins

Abstract

Nearly 30 years after Stewart and colleagues presented data showing an increased risk of cancer for children who were exposed to diagnostic x-rays while in utero,¹ the meaning of this association remains unclear. Although the observation has not been reproduced in a few smaller studies, the larger studies and the bulk of the evidence suggest that the association exists.² The uncertainty concerns its explanation. Bithell and Stewart express the view that it is evidence of a causal connection between the radiation exposure and increased cancer risk.³ Others are more inclined to look for some characteristic of the mother, the child, . . .