This chapter outlines the typical nutritional needs for a pregnant woman, reviews some of the unique issues of administering adequate nutrition for the benefit of the maternal-fetal dyad, and provides an overview of some of the more common clinical situations. Inadequate maternal nutrition may be associated with a low infant birth weight and is significantly correlated with later development of adult diseases such as cardiovascular disease, stroke, obesity and type 2 diabetes mellitus, even when adjusting for lifestyle factors. The initial focus for nutritional supplementation should be to optimize the micronutrients, avoid hypo- or hyperglycemia, and maintain an appropriate fluid balance. As the situation stabilizes, then efforts towards adequate macronutrients and calories can be undertaken, while avoiding refeeding syndrome, avoiding overfeeding, and balancing the iatrogenic complications of aggressive enteral nutrition (EN) or parenteral nutrition (PN) against the risks of underfeeding.