EMMA's work was published in July of this year in the American Economic Journal. Emily Oster and Emily Fitzsimmons: We need to be supporting moms more if they want to breastfeed for any reason. You may have heard that earlier this year there was a large shortage of baby formula in the US. This got me thinking about moms who might have decided to breastfeed or continue breastfeeding because formula was less available. Could that be another natural experiment to study the impact of breastfeeding?