The menstrual cycle is a physiological process that occurs with cyclic changes in the levels of many hormones. A leading role in these processes is occupied by estrogen, which, in addition to reproductive health, controls many other tissue processes. Functional amenorrhea – absence of menstruation of hypothalamic origin is a common form of secondary amenorrhea, which leads to estrogen deficiency in premenopausal women. The causes of this disease are psychological stress, excessive physical activity, eating disorders, as well as the combined action of the mentioned factors, which suppresses the hypothalamus-pituitary-ovary axis. Low estrogen levels have a multifaceted effect on the body, and in particular on the cardiovascular system, musculoskeletal system and reproductive health. The consequences of the deficiency of this hormone in premenopausal and menopausal women are well studied. They have an increased cardiovascular risk, an increase in cholesterol and a worsening of hypertension. In addition, bone density decreases and the risk of osteoporosis and fractures increases, as well as disorders in the mental health of patients are observed. One of the leading causes of secondary amenorrhea is functional amenorrhea of ​​hypothalamic origin, which results in significantly low estrogen levels and cessation of the menstrual cycle. The mechanism leading to this condition is based on suppression of the action of gonadotropin-releasing hormone on the hypothalamic-pituitary-ovarian axis. This leads to a decrease in the serum concentration of the luteinizing – LH and follicle-stimulating – FSH hormones, due to their reduced release from the anterior lobe of the pituitary gland. For this reason, the cells in the ovaries do not receive the necessary signals that regulate the secretion of estrogen. Thickening of the endometrium, which is a natural process occurring under physiological conditions, within each menstrual cycle, does not occur during the follicular phase. This leads to amenorrhea. The consequences of not menstruating on cardiovascular health are significant. Under physiological conditions, estrogen has a vasodilating effect and protects against inflammatory processes and oxidative stress in the vessels. Low levels of estrogen lead to affecting the coronary vessels of the heart and accelerating atherosclerotic changes in them. In the presence of stress in everyday life, the production of hormones, at the central level, which stimulate the function of the ovaries, is reduced. This leads to an imbalance in the hormones that are important for the proper course of the menstrual cycle. Menstruation becomes irregular, disorders in reproductive health are also observed – the chances of becoming pregnant decrease significantly due to loss of ovarian function. Estrogen plays a key role in bone metabolism. It stimulates the activity of osteoblasts – cells that are important for bone building.With a lack of estrogen, increased cell death of these cells and increased activity of osteoclasts, important for the processes of bone tissue degradation, are observed. Low levels of estrogen disrupt the absorption of calcium in the intestinal tract, which reduces the availability of this element for building bones. These changes lead to osteoporotic damage to the musculoskeletal system and an increased risk of fractures. Higher serum concentrations of the stress hormone cortisol are observed in patients with amenorrhea of ​​hypothalamic origin. This has a negative impact on bone health through two mechanisms – it disrupts vitamin D metabolism, as well as the metabolism of calcium and other hormones that are important for bone health. Hypothalamic amenorrhea can lead to a decrease in the function of the thyroid gland – hypothyroidism, as it affects the processes in which this gland takes part. In patients with hypothalamic amenorrhea, decreased levels of triiodothyronine – T3 and thyroxine – T4 are observed, while the levels of thyroid stimulating hormone – TSH remain unchanged. The condition also leads to reproductive health disorders. Decreased secretion of gonadotropin-releasing hormone disrupts the release of LH and FSH, resulting in estrogen deficiency and lack of ovulation. Low levels of estrogen disrupt the formation of follicles from the ovaries and thus prevent the maturation of eggs within each menstrual cycle. The release of mature eggs is also disrupted and they cannot reach the fallopian tubes where fertilization takes place. References: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6374026/Low levels of estrogen disrupt the formation of follicles from the ovaries and thus prevent the maturation of eggs within each menstrual cycle. The release of mature eggs is also disrupted and they cannot reach the fallopian tubes where fertilization takes place. References: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6374026/Low levels of estrogen disrupt the formation of follicles from the ovaries and thus prevent the maturation of eggs within each menstrual cycle. The release of mature eggs is also disrupted and they cannot reach the fallopian tubes where fertilization takes place. References: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6374026/