Current knowledge of obesity's effects in the pre- and periconceptional periods and avenues for future research.

The prevalence of obesity is growing among reproductive-age women. This is concerning because obesity has significant health-related consequences. Aside from the long-term risks of diabetes, heart disease, and some types of cancer, obesity poses immediate threats for young women including subfertility and adverse early and late pregnancy outcomes. Epidemiologic and experimental studies demonstrate associations between prepregnancy obesity and poor reproductive outcomes; however, the mechanisms involved are poorly understood. We discuss current knowledge of the pathophysiology of obesity in early reproductive events and how these events may affect reproductive outcomes including fertility and miscarriage risk. We also discuss avenues for future research and interventions to improve reproductive outcomes for obese women.