Perhaps in early gestation, high plasma concentrations of maternally-derived ghrelin that would occur during states of malnutrition may act as an 'embryonic termination' signal to circumvent the excess metabolic demands of pregnancy, but in mid to late gestation placenta-derived ghrelin in the normal concentration range may be essential for the growth and development of the fetus. This evidence concerns the gene GHRL and nutritional deficiency disease.