No previous study has attempted to estimate the eect of intrauterine exposure to armed con‡ict, a potential source of stress, on pregnancy outcomes. Drawing on data from the 2004 Palestinian Demographic and Health Survey, we examine the relationship between fatalities caused by Israeli security forces (a measure of con‡ict intensity) and birth weight. Our estimates suggest that …rst-trimester fatalities are positively related to the probability that a child weighed less than 2,500 grams at birth. This result is consistent with medical studies showing a strong negative correlation between self- reported stress during the …rst trimester of pregnancy and birth weight.