ABSTRACT. Extremes in nutrition and aging play important roles in infertility and the health status of the mother and the newborn. Using animal models, it has been shown that follicular population, the quality of the oocyte, and uterine receptivity are sensitive to short- and long-term effects of nutrition, which affect the outcome of natural and artificial reproductive techniques. The establishment of pregnancy that depends on an adequate synchrony between the embryo and the endometrium is altered by over- and undernutrition. While overnutrition in early pregnancy can increase embryo losses due to an increase in progesterone clearance from circulation, subnutrition induces a decrease in the expression of progesterone receptors in the endometrium and in the concentrations of metabolic hormones and their receptors in the endometrium and the oviduct. Education and enhanced awareness of the effect of nutrition and age on fertility are essential in counseling patients who desire pregnancy. © 2015 Elsevier Inc. All rights reserved.