The role of melatonin in the implementation of women's reproductive plans: from menarche to the physiological course of the gestational process (literature review)

The indoleamine hormone melatonin, with its many physiological and biological functions, is now considered an important and essential hormone during pregnancy. Melatonin is an antioxidant, anti-inflammatory agent, free radical scavenger, circadian rhythm regulator, and sleep hormone. Aim: to analyze the current data on the effect of melatonin on reproductive function, pregnancy and fetal development, and the issues of exogenous melatonin administration in obstetrics and gynaecology. Recent studies have shown that the placenta can synthesize its melatonin, which acts as an antioxidant and anti-inflammatory agent, providing a stable environment for both mother and fetus. Thanks to its antioxidant properties, the integrity of the placenta is maintained. During physiological pregnancy, the mother's immune system is constantly changing, and melatonin acts as a key anti-inflammatory factor that regulates immune homeostasis in the early and late stages of pregnancy. Excessive production of oxygen and nitrogen metabolites are important mediators of cell and tissue damage. It is melatonin, which is easily transferred from the maternal circulation to the fetus, that may be a protective factor that will prevent free radical damage to the fetus and contribute to better perinatal outcomes. The antioxidant properties of melatonin have been shown to optimize the reproductive physiology of pregnant women by eliminating undesirable oxidative and nitrosative reactions in ovarian, uterine, and placental cells. It is emphasized that melatonin is an important factor for the course of early pregnancy, for the normal development and functioning of the placenta. It has been determined that the circadian release of this hormone is involved in the correction of various pathological conditions that occur during pregnancy: dyssomnia, pre-eclampsia, paroxysmal eclampsia. It has been shown that exogenous melatonin supplementation in pregnant women contributes to the regression of sleep disorders, pre-eclampsia, fetal growth retardation, and normalization of adrenal corticosterone levels. No conflict of interests was declared by the authors.