Experience in being pregnant is exciting but is very challenging. The term "undernutrition," as used in this chapter, focuses more on inadequate intake of energy and nutrients to meet the desired outcome of a healthy mother and her baby. Evidence shows that women with undernutrition before and during pregnancy have increased risk of metabolic disorders (i.e., gestational diabetes mellitus) and are at increased risk of complications during labor and birth. To date, nutritional therapies promoting healthier pregnancies fall into the following two major categories: (1) management of gestational weight gain and (2) the prevention or treatment of nutrient deficiencies related to pregnancy. A literature search on PubMed, the Cochrane library, Google scholar, and Cumulative Index of Nursing and Allied Health Literature was conducted to identify the relevant nutritional therapies. As a result, this chapter will analyze and discuss gestational weight gain and its effect on the health of women and her baby. The chapter briefly proposes evidence-based nutritional therapy for gestational diabetes as well as gestational common nutrient imbalance, such as vitamin D, folic acid, and omega-3 docosahexaenoic acid deficiency. The recommendations, in this chapter, would be a partial answer for these problems in Asia.