Childbearing is a period in the life cycle during which some women may gain weight, become overweight, or become obese. Despite guidelines issued in 1990 for gestational weight gain, many women exceed them. Women who are overweight before pregnancy are most vulnerable to excessive gestational weight gain. Prenatal interventions to prevent excessive gain have had mixed results. During the postpartum period, 14% to 20% of women may retain weight from pregnancy, which elevates risk of later health problems. Although postpartum weight loss interventions have been shown to have efficacy, these have been tested primarily with White women. Continued efforts are needed in practice and research to develop effective approaches for managing weight during pregnancy and postpartum, especially for low-income and ethnic minority women.