Ouidir M, et al. – This nationwide study investigated the individual (socioeconomic and behavioural) and contextual factors related to atmospheric pollution exposure during pregnancy. As per findings, social inequalities in atmospheric pollutants exposure, were evident, according to contextual characteristics such as urbanisation level and social deprivation and also according to individual characteristics such as education, being in a relationship and smoking status. In French urban areas, exposure to health–threatening atmospheric pollutants was greatest among pregnant women from the most deprived neighbourhood.