Pregnancy offers an opportunity to influence nutritional health for both the pregnant woman and the infant. Nutrition influences the likelihood of both high- and low-birth-weight infants and long-term risks of developing metabolic diseases in adulthood. A healthy weight at conception has the potential to improve the experience and outcomes of pregnancy. However, nutritional assessment and calculation of nutritional requirements pose many questions including the need for some micronutrients more than macronutrients during pregnancy. This review provides an overview of the evidence in nutrition assessment and pregnancy.