Menorrhagia can be caused by abnormalities in the function of various organs, including the hypothalamus, pituitary gland and ovaries. If there is only 1 missed period, then there is no need for excessive worry and treatment. If you have not had a period for more than 3 months in a row, or if you are 15 years old and have not had your first period, you need to seek medical attention to find the cause of the abnormal period or even amenorrhea after excluding pregnancy, and then treat it according to the different causes. In this article, we will briefly introduce several treatment options for amenorrhea. (1) Polycystic ovary syndrome: In patients with polycystic ovary syndrome, oral contraceptives are the first line of treatment. Oral contraceptives can inhibit the hypothalamic-pituitary-ovarian axis and reduce the overproduction of androgens in the ovaries, thus serving to regulate menstruation, reduce symptoms of hirsutism, and prevent endometrial hyperplasia and endometrial cancer. In addition, you can also improve your body metabolism through exercise and oral metformin to promote the recovery of ovulatory cycle. (2) Functional hypothalamic amenorrhea: Functional hypothalamic amenorrhea is often caused by excessive dieting, excessive exercise and stress. Restoring a normal diet, reducing exercise intensity, and relieving emotional stress can effectively reverse functional hypothalamic amenorrhea. If the patient wishes to continue high-intensity exercise, such as athletes, or if the nutritional status cannot be effectively improved, estrogen and progestin replacement therapy can also be applied to allow the patient to return to a normal menstrual cycle. (3) Hyperprolactinemia: Dopamine agonists are the first-line agents used in the treatment of hyperprolactinemia. Dopamine agonists can be used to lower blood prolactin levels and control tumor size in patients with pituitary prolactin adenomas. If symptoms are not well controlled, surgical resection is performed. If the prolactinoma is poorly located and difficult to completely remove surgically, radiation therapy may also be used to control the prolactinoma. In patients with idiopathic hyperprolactinemia, dopamine receptor agonists are also used as first-line agents. (4) Primary ovarian insufficiency: Exogenous hormone replacement therapy can be considered in patients with amenorrhea due to primary ovarian insufficiency. Unless the patient has contraindications to estrogen, such as venous thrombosis, hormone replacement therapy is usually continued until about age 50, which is the perimenopausal period. Hormone replacement therapy is not only effective in preventing vaginal atrophy and maintaining sexual function, but also in reducing the risk of osteoporosis and coronary heart disease associated with estrogen deficiency. (5) Abnormal hypothalamic function: In some patients with irreversible abnormal hypothalamic function, such as congenital GnRH deficiency, estrogen can be used to promote the development of breast, bone and endometrium. Progestin is added after the patient’s secondary sexual characteristics have matured to prevent endometrial hyperplasia and establish an effective menstrual cycle. In patients with a need for pregnancy, gonadotropin-releasing hormone (GnRH) or pulsatile addition of GnRH can be added externally, thus inducing ovulation. (6) Uterine adhesions: Uterine adhesions such as Asherman syndrome can be treated by hysteroscopy to reach deep inside the uterine cavity and instrumentation to separate the adherent tissue. (7) Congenital anatomical anomalies: anatomical anomalies usually require surgical interventions depending on the disease. There are appropriate surgical options for various reproductive system anomalies such as transverse vaginal septum, mullerian duct developmental malformation, and imperforate hymen. (8) Thyroid disorders: Patients with thyroid disorders are often associated with menstrual disorders, and amenorrhea is more common in patients with hypothyroidism than in those with hyperthyroidism. Patients with hypothyroidism tend to present with excessive menstruation, but some people also present with secondary amenorrhea. Patients with amenorrhea due to hypothyroidism need to take levothyroxine, have their thyroid function monitored regularly, and have their TSH stabilized at 0.5-5.0 mU/L by adjusting the dosage according to their thyroid function level. hyperthyroidism can be treated with medication, radioactive iodine, or surgery. In summary, there are various causes and treatments for amenorrhea. Some rare diseases causing amenorrhea such as tuberculous endometritis, androgen insensitivity syndrome, and Turner syndrome are not described in detail in this article, but all possibilities of the causes of amenorrhea should be considered in conjunction with the patient’s medical history, physical examination, and ancillary tests, and then tailored to the disease.