Hyperthyroidism usually results in decreased menstruation. Normal menstruation occurs in response to luteinizing hormone and follicle-stimulating hormone, both of which are produced in the pituitary gland in response to gonadotropin-releasing hormone secreted by the hypothalamus. Hyperthyroidism in patients affects the hypothalamic-pituitary-ovarian axis, causing a decrease in gonadotropin-releasing hormone, luteinizing hormone, and follicle-stimulating hormone, which ultimately leads to decreased menstruation. Because of the increased basal metabolic rate in hyperthyroidism, fat catabolism is higher, and the synthesis of many sex hormones is aided by the need for steroids, which require fat synthesis. Thus sex hormones are affected menstruation is further reduced. Therefore, if hyperthyroidism is diagnosed, it should be treated regularly under medical supervision.