Although relationships between economic and demographic changes have often been debated, studies have long remained focused on urban and industrial areas. Converging evidence, however, suggests that early birth control emerged in rural Wallonia. The aim of this article is to examine the dynamic relationship between economic and demographic changes. We start from the theoretical assumption that regions where early birth control is observed are actually spaces where populations did not have alternative means of dealing with a rupture in the balance between resources and populations. Preliminary results seem to support the idea that the theoretical framework of “demographic regimes†provides an interesting perspective for analysing interactions between economic context and population dynamics. Low fertilities observed very early during the 19th century in the south of rural Wallonia would thus be the result of modified behaviours allowing populations to face precarious living conditions. Most of the time, birth control took place in typical 19th-century crisis contexts. However, this demographic solution, which was probably initially intended to respond temporarily to a modification of the context, would have turned into a structural and inherent feature when birth control became generalised to all spaces and populations.