High serum prolactin suggests hyperprolactinemia, a state in which peripheral serum prolactin levels are persistently higher than normal for a variety of reasons is called hyperprolactinemia. The causes of hyperprolactinemia are manifold: 1. idiopathic hyperprolactinemia. It is mostly due to the patient’s hypothalamic-pituitary dysfunction, resulting in increased prolactin secretion.2. Pathological hyperprolactinemia. Autonomous high-functioning pituitary prolactin adenomas are common. Pituitary adenomas account for 10%-15% of all intracranial tumors, and are mostly benign tumors with a size of <10mm, called microadenomas.3. Pharmacological hyperprolactinemia. It is mainly caused by drugs that antagonize the hypothalamic prolactin-releasing inhibitory factor or enhance the excitation of prolactin-releasing factor.4. Physiological hyperprolactinemia. Such as pregnancy, breastfeeding, puerperium, nipple stimulation, etc., can lead to a temporary increase in prolactin levels.