Formation of the Menstrual Cycle in Adolescent Girls and Hormonal Changes During Puberty

Puberty is a complex biological transition during which the child’s body gradually acquires reproductive, endocrine, somatic, and psychosocial maturity. In adolescent girls, one of the most important markers of pubertal development is the onset and subsequent maturation of the menstrual cycle. Menarche, or the first menstrual bleeding, usually occurs after the activation of the hypothalamic–pituitary–gonadal axis and reflects the progressive interaction between the hypothalamus, pituitary gland, ovaries, uterus, and peripheral endocrine tissues. However, the establishment of regular ovulatory cycles does not occur immediately after menarche. During the first postmenarchal years, menstrual cycles are often irregular because the neuroendocrine mechanisms controlling gonadotropin-releasing hormone, luteinizing hormone, follicle-stimulating hormone, estrogen, and progesterone secretion are still maturing. This article discusses the physiological formation of the menstrual cycle in adolescent girls, the hormonal changes of puberty, normal and abnormal menstrual patterns, and the clinical importance of monitoring menstruation as an indicator of adolescent reproductive health.