Maternal stress during pregnancy can have significant implications for both maternal health and well-being and affect pregnancy outcomes. Various sources of maternal stress may emerge throughout the gestational period. This chapter examines the psychological, obstetrical, biological, and social factors contributing to maternal stress from conception to delivery. It provides an overview of existing evidence on the diverse stressors encountered during pregnancy and investigates the mechanisms through which they affect maternal health and pregnancy outcomes. By integrating these factors, the chapter emphasizes the importance of a comprehensive understanding of maternal stress within prenatal care.