We investigate how birth weight in Argentina responds to monthly economic ‡uctuations around the economic collapse of December 2001, and document its procyclicality with respect to the month of birth during [2001][2002][2003]. Our data reveal that this procyclicality is driven by children born to low-educated mothers. We exploit the fact that the impacts of maternal nutrition and stress on birth weight vary according to the stages of gestation. We …nd evidence that the birth weights of children to loweducated mothers are sensitive to macroeconomic ‡uctuations during both the …rst and third trimester of pregnancy, while those of high-educated mothers only react to the …rst trimester of pregnancy. Our results are consistent with low-educated women facing credit constraints and su¤er-ing from both nutritional deprivation and maternal stress, while higheducated women are only a¤ected by stress.