Melatonin and childbearing: Part 1. Preimplantation period and implantation

Melatonin is a hormone produced in terrestrial vertebrates and humans in the pineal organ, an endocrine gland. It was established that one of the major functions of melatonin is the synchronization of the function of all organs and the regulation of seasonal and diurnal rhythms of their physiological activity. The synchronization function and rhythm regulation are performed in accordance with the circadian rhythm of melatonin expression, depending on the length of day and night. Melatonin is able to influence the growth, development, and physiological activity of different types of cells, affecting the mechanisms of signaling pathways and cascades similarly to growth factors. It was confirmed that the processes of conception, pregnancy, and childbirth directly depend on the rhythm and secretion profile of the epiphyseal hormone melatonin in the body. In this review, we attempt to combine the available published data on the involvement of melatonin in various physiological processes during the preimplantation and postimplantation periods of life of the organism and its positive and negative effects at the stages of puberty.