Risk factors associated with intrauterine growth restriction (IUGR) have previously been identified, but few studies have described the relationship between IUGR and maternal stress caused by exposure to civil unrest. Here, we investigate this relationship during the Mount Elgon crisis in western Kenya between 2006 and 2008, following a period of violence. Birth weight data were compared between three hospitals in an exposed area, Mount Elgon (n=570), and one hospital in a control area, Kimilili (n=530). In a sub-analysis, the most stress exposed hospital, Bungoma West (n=211), was compared with the control hospital in Kimilili. Adjustments were made for offspring sex, gestational age and parity. The difference in mean birth weight between the most stress-exposed hospital (Bungoma West) and the control hospital (Kimilili) was 91 g after full adjustment (P=0.041). In conclusion, epidemiological data suggest a significant relationship between exposure to civil unrest and IUGR causing lower birth weight.