INS and Infertility: Luteal phase deficiency in natural cycles is an important cause of infertility and pregnancy loss.38 It is well established that pubertal activation of the reproductive axis and maintenance of fertility are critically dependent on the magnitude of body energy reserves and the metabolic state of the organism.39 As paradigmatic example, much has been learned on the reproductive roles of key metabolic hormones (such as leptin, insulin and ghrelin).40 The DEGs were not only related to reproduction-related pathways but also in those associated with nutrient metabolism.