Although relationships between economic and demographic changes have been debated several times, they have long remained focused on urban and industrial areas. Converging evidences however suggest that early birth control have been emerging in rural Wallonia. The aim of this article is to examine the dynamic 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 any other alternatives to deal with a break in the balance between resources and populations. The preliminary results seem to support the idea that the theoretical framework of “demographic regimes” provides an interesting perspective to analyze 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 adjusted behaviors that allow populations to face precarious living conditions. Most of time, birth control took place in typical 19th-century crisis contexts. However, this demographic answer, which was probably initially intended to respond momentarily to a modification of the context, would have turned into a structural and inherent feature when birth control became generalized to all spaces and populations.