Nber Working Paper Series the Benefits of Breastfeeding across the Early Years of Childhood

The choice to breastfeed rather than formula-feed an infant as well as the duration of doing so has been scrutinized in more recent times. Yet, key identification issues remain to be resolved, including the array of possible child development benefits, the optimal intensity of breastfeeding versus formulafeeding, and the possibility of confounding with other inputs that promote child health. This study uses the Early Childhood Longitudinal Survey – Birth Cohort to explore the causal effect of breastfeeding on development across the early years of childhood. We examine a range of health, physical, and cognitive outcomes and relate these to a set of breastfeeding and formula-feeding intensities. Adjusting for a very extensive set of potential confounding factors that also promote child development, our empirical method uses simultaneous equations models and propensity score measures to understand the link between breastfeeding and child outcomes. Our results indicate that breastfeeding and not formula-feeding at birth are associated with increased probabilities of being in excellent health at 9 months. Furthermore, they are protective against obesity and improve cognitive outcomes at 24 months and 54 months. Breastfeeding for 6 months or more increases motor scores at 9 months. Clive R. Belfield Queens College / CUNY Economics Department 300 Powdermaker Hall 65-30 Kissena Boulevard Flushing, NY 11367 [email protected] Inas Rashad Kelly Queens College / CUNY Economics Department 300 Powdermaker Hall 65-30 Kissena Boulevard Flushing, NY 11367 and NBER [email protected]