Prolactin (PRL), also known as prolactin, is a hormone secreted by the pituitary gland. Prolactin is secreted in women during late pregnancy and lactation to promote breast development and lactation. The maximum serum PRL level in non-pregnant women usually does not exceed 26 ng/ml. If the PRL level in the blood is too high, it is called hyperprolactinemia. These individuals often have overflowing breast milk, scanty menstruation or even amenorrhea. This is why it is also called amenorrhea-a-lactation syndrome. When there is too much prolactin in the body, it can inhibit the secretion of gonadotropins from the pituitary gland and directly affect the synthesis of sex hormones in the ovaries, resulting in low serum estrogen levels, which can cause ovarian dysfunction, reduced ovulation, or no ovulation, or even amenorrhea. The following are some of the common causes of elevated prolactin: 1. Nerve stimulation: due to stimulation of the skin in certain areas, especially the chest, can cause increased prolactin through nerve transmission to the hypothalamus. For example, burns, herpes zoster on the chest and back, etc. All belong to the causes of high prolactin in women. 2, pituitary disorders: various tumors in the pituitary gland area, mainly pituitary tumors, pituitary adenomas lead to high prolactin, part of the pituitary gland hyperfunction, can cause overflow, amenorrhea. 3, drug factors: sedatives of the central nervous system, which reduce the level of hypothalamic catecholamines and reduce the activity of prolactin-releasing factors produced by the hypothalamus. 4, primary hypothyroidism: hypothyroidism is the cause of high prolactin, causing the hypothalamus to produce large amounts of thyrotropin-releasing factor, which also stimulates the overproduction of pituitary prolactin when stimulating the pituitary gland to secrete thyrotropin. 5, other: chest wall injury, renal insufficiency, malignant tumors in other areas, etc.