Authors: Rocio Alvarez-Aranda (Universidad Central), Serafima Chirkova (Universidad de Santiago de Chile), Jose Gabriel Romero (Universidad de Santiago de Chile)
We use administrative data on the Chilean birth records to study how prenatal maternal stress, caused by sustained seismic activity in Chile, affects birth outcomes during the period 2011-2015. Our mother-fixed-effect model together with the spatiotemporal variation of earthquakes in Chile allow us to adress identification issues that have obscured previous estimates. We find positive impacts of prenatal stress on birth outcomes; and these findings reflect possible consequences of potential failures in fetal growth. Our estimates suggest that for more affluent mothers, changes in gestational length explain a great part of variation in birth weight. Once we adjust for growth standards there is no significant impact on the newborns small and large for gestational age. These mothers seem to react to earthquake by adapting their behavior to mitigate negative impacts, resulting in an unaffected fetal growth rate. For less affluent mothers, a great part of variation in birth weight is left unexplained by changes in gestational age. This result points to prenatal stress as a possible cause for accelerated fetal growth, leading to a higher proportion of babies large for their gestational age.