Evidence for similar changes in offspring phenotype following either maternal undernutrition or overnutrition: potential impact on fetal epigenetic mechanisms.

The goal of this review is to shed light on the role of maternal malnutrition in inducing epigenetic changes in gene expression, leading to alterations in fetal growth and development, and to altered postnatal phenotype and the development of metabolic disease. We present evidence supporting the concept that both maternal undernutrition and overnutrition can induce the same cadre of fetal organ and tissue abnormalities and lead to the same postnatal metabolic changes in the resulting offspring. Furthermore, we present evidence that in both overnourished and undernourished ovine pregnancies, fetuses experience a period of nutrient restriction as a result of alterations in placental delivery of maternal nutrients into the fetal compartment. We argue that this bout of reduced fetal nutrition in undernourished and overnourished pregnancies leads to the development of a thrifty phenotype in which the fetus attempts to alter the function of its tissues and organs to maximise its chances of survival in a postnatal environment that is deficient in nutrients. Importantly, we present evidence to support the concept that these phenotypic changes in offspring quality resulting from maternal malnutrition are transmitted to subsequent generations, independent of their maternal nutritional inputs.