Valuing five centuries of unpaid breastfeeding in England.

Breastfeeding is vital and valuable labor, contributing to the physical and cognitive health of children throughout their lives, yet it is rarely compensated in formal labor markets. Its economic importance may therefore go unrecognized. We impute upper and lower bounds for the value of unpaid breastfeeding over five centuries in England to better understand its economic role over the course of economic development. We also contribute an estimate of changes in breastfeeding duration over this period from historical and bioarchaeological sources using interval regression. At minimum, unpaid breastfeeding consistently exceeded 0.1% of gross domestic product (GPD), reaching a possible peak of 6.58% in the sixteenth century while the wider economy stagnated. This quantity exceeds expenditures on school and apprenticeship, making breastfeeding possibly the largest source of human capital investment in early modern England. Yet the relative value of unpaid breastfeeding gradually declined as the wider economy grew. Indeed, for much of English history the income elasticity of breastfeeding appears to have been negative, only becoming positive at some point in the nineteenth century. Because breastfeeding was strongly negatively correlated with infant mortality, this challenges longstanding assumptions about the relationship between income and mortality. In sum, breastfeeding was not a biologically determined constant but a dynamic, if neglected, part of economic life.