The role of marital fertility in Irish population history, 1750-1840

Abstract

and controversy. One problem concerns the cause of the rapid population growth in the second half of the eighteenth century and the first decades of the nineteenth. Irish population data are of such poor quality that several hypotheses can be plausibly advanced. A rise in levels of nuptiality and a decline in mortality have both been suggested as explanations. To these Mokyr and 0 Grada have more recently added the possibility of a rise in marital fertility. In their survey of Irish population history during the period I700-i850 they note that the relatively high Irish birth rate in i840 is explained principally by a high level of marital fertility compared with other west European countries. Nuptiality levels resembled those elsewhere in western Europe. They concluded that while the propensity to marry probably played a major role in Irish population growth in the eighteenth century as Connell postulated, the true picture is more complex. Marital fertility was exceptionally high in Ireland in i840, and it seems at least likely that this variable played an equally important role in the century prior to the Great Famine.2 Mokyr and 0 Grada also reviewed a list of possible causes of the relatively high marital fertility in pre-Famine Ireland. They mentioned 'higher fecundity, social or religious taboos on contraception, and a desire for large families' as possible causes.3 This note aims to show that the employment of a logical framework imposed by demographic constraints may limit the number of possible solutions to questions about the causes of Irish population growth and relatively high marital fertility. For instance, using stable population theory and a fertility model, it can be shown that a rise in marital fertility is unlikely to explain the whole increase in the growth rate in Ireland. Studies of the determinants of marital fertility suggest that only two proximate determinants4 of marital fertility need to be considered in this context. Using additional information supplied by Mokyr and 0 Grada, I shall suggest that the duration of the post-partum non-susceptible period, which is strongly influenced by breastfeeding patterns, was the more likely