What are the causes and classifications of amenorrhea?

Whether it is primary amenorrhea or secondary amenorrhea, the causes of its occurrence have both similarities and differences. The normal menstrual cycle is regulated by the endocrine function of each link of the hypothalamus-pituitary-ovarian axis. If any link is impaired, menstrual disorders will occur, sometimes leading to amenorrhea. There are four main links that control the normal menstrual cycle. We will analyze each link one by one.

⑴ Uterine amenorrhea: The cause of amenorrhea is in the uterus. The menstrual regulation function is normal and the ovaries are functional, but the endometrium cannot produce a normal response to the ovaries, so it is called uterine amenorrhea. Common diseases that cause uterine amenorrhea include: endometrial damage or adhesion syndrome, endometritis, incomplete or absent uterus, after hysterectomy or intrauterine radiotherapy.

⑵ Ovarian amenorrhea: The cause of amenorrhea lies in the ovaries. The level of ovarian sex hormones is low, and the endometrium does not undergo cyclical changes, resulting in amenorrhea. Common diseases include: congenital ovarian hypoplasia or absence, premature ovarian failure, ovarian removal or tissue destruction, and ovarian tumors.

⑶ Pituitary amenorrhea: The main lesion is in the pituitary gland. Organic diseases or dysfunction of the anterior pituitary gland can affect the secretion of gonadotropin, thereby affecting the ovaries and causing amenorrhea.

⑷ Hypothalamic amenorrhea: It is the most common type of amenorrhea. Amenorrhea is caused by hypothalamic dysfunction affecting the pituitary gland and then the ovaries. Its etiology is complex and can be caused by organic lesions of the central nervous system, mental factors, systemic diseases, drugs and other secretion disorders.