Prenatal care providers are advised to evaluate maternal weight at each regularly scheduled prenatal visit, monitor progress toward meeting weight gain goals, and provide individualized counseling if significant deviations from a woman’s goals occur. Today, nearly 50% of women exceed their weight gain goals with overweight and obese women having the highest prevalence of excessive weight gain. Risks of inadequate weight gain include low birth weight and failure to initiate breastfeeding whereas the risks of excessive weight gain include cesarean deliveries and post-partum weight retention for the mother and large for gestational age infants, macrosomia, and childhood overweight or obesity for the offspring. Prenatal care providers have many resources and tools they can use to incorporate weight and other health behavior counseling into their routine prenatal practices. Because many women are motivated to improve their health behaviors, pregnancy is often considered the optimal time to intervene for issues related to eating habits and physical activity so as to prevent excessive weight gain. Gestational weight gain is a potentially modifiable risk factor for a number of adverse maternal and neonatal outcomes and meta-analyses of randomized controlled trials report that diet or exercise interventions during pregnancy can help reduce excessive weight gain. However, health behavior interventions for gestational weight gain have not significantly improved other maternal and neonatal outcomes and have limited effectiveness in overweight and obese women.