The time spanning from before conception to birth represents a critical period for both maternal and fetal health, with important implications for later development of chronic medical conditions. Reproductive and perinatal epidemiology is a well-established subspecialty of epidemiology characterized by unique methodological challenges, including time-varying exposures, clustering of units of analysis, and measurement of rare exposures and rare outcomes. This course will examine, in detail, methodological approaches and challenges in reproductive and perinatal epidemiology. Topics will cover design, measurement, and analysis in studies of fecundity and fertility, pregnancy and maternal health, and birth outcomes. Critical evaluation and design of research study proposals are a major focus of this course.