The effect of media coverage of the London terrorist attacks on 7 July 2005 on pregnancy outcome in mothers living in the North Western region of England was assessed. Pregnant women exposed to media coverage of these attacks had infants with mean birth weight lowered by 16 g and increased risks of a small and very small for gestational age infant (odds ratio 1:10 and 1:09, respectively). This small, but significant reduction in birth weight may indicate excess glucocorticoid exposure within the fetus, which could contribute to fetal programming and an increased likelihood of disease in adult life.