One of the great wonders of Nature is the growth of a fetus within its mother. Amazingly, the fetus manages not only to prevent immune-mediated attack as a foreign antigen, but also to reroute the mother's nutrient metabolism so as to sustain the fetal requirements for rapid intrauterine growth. Thus, even in a healthy mother, the metabolic demands of pregnancy can cause significant nutrient deficits. Furthermore, the hormonal milieu of pregnancy can unmask or exacerbate maternal diabetes mellitus, hypertension, hyperlipidemia, and cardiorespiratory insufficiency. The role of proper nutrition in avoiding these complications is well recognized, although not as well applied. This article briefly reviews nutrient metabolism and nutrient requirements during pregnancy, discusses the nutritional assessment of the pregnant woman, and reviews modalities of nutritional support for hyperemesis gravidarum (HG) and other medical conditions.