Menstruation usually normal suddenly postponed

The establishment and maintenance of normal menstruation depends on the neuroendocrine regulation of the hypothalamic-pituitary-ovarian axis, the periodic response of the target organ endometrium to sex hormones, and the patency of the lower reproductive tract, any of which can cause menstrual delay. Common causes include polycystic ovary syndrome, premature ovarian failure, mental stress, weight loss and anorexia nervosa, exercise training such as long-term strenuous exercise, drug-induced amenorrhea, pituitary microadenoma, repeated curettage resulting in endometrial damage, etc.