Pregnancy represents a unique period in life with considerable potential to influence not only maternal health but also that of future generations. Poor maternal nutritional status, along with maternal body composition, metabolism, and placental nutrient supply, are the main factors that can negatively or positively influence fetal development and have been strictly related to adverse pregnancy outcomes and expression of fetal genetic potential. Adequate energy and nutrient intake are pivotal in pregnancy and should begin before conception and continue throughout pregnancy to support the usual maternal needs in addition to fetal development. Nutritional deficiencies during pregnancy remain a public health concern, particularly in underprivileged and high-risk populations, supporting the importance of an individualized approach and eventually to a tailored supplementation.