I examine whether socially stratified medicalization was a factor in the European fertility transition. The transition refers to a general decline in birth rates due to effective use of birth control within marriage. The project is based on the hypothesis that between the 17th and 20th century health was increasingly perceived as manageable. In this project I focus on maternal health. This refers to the physical wellbeing of mothers in general, but also more specifically to health issues related to pregnancy and childbearing. Although hospital statistics and figures on death in childbed will be used to frame the analysis, it is not my aim to reconstruct the actual social and geographical differentials in maternal health and the real impact of medical improvements thereon. Instead, I concentrate on social and regional variation in the perceptions of health, health care and health risks and their effect on reproductive outcomes. By the early 20th century pregnancies and births were regarded as challenging for women’s physical wellbeing and preserving good health became a major motivation to limit family size. I use quantitative and qualitative micro-level methods to analyze how these ideas have developed in the long run in a socially layered diffusion process in earlier centuries in two different demographic contexts, Flanders and Lazio.