Among nearly 10 million US infants born between 2016 and 2018, breastfed babies were 33% less likely to die during the post-perinatal period (day 7−364) than infants who were not breastfed, reports a new study in the American Journal of Preventive Medicine, published by Elsevier. The findings build on previous US research with smaller datasets, which documented the association between the initiation of breastfeeding and the reduction of post-perinatal infant mortality by a range of 19% to 26%.