High pituitary prolactin may be related to physiological factors, but it may also be caused by pituitary tumor, idiopathic hyperprolactinemia, hypothyroidism and other diseases. 1. Physiological factors: It is normal for pregnant or lactating women to have high pituitary prolactin, which is to promote breast development and prepare for breastfeeding, and after the lactation period, the prolactin will be lowered and return to normal. 2. Pathologic factors: (1) Pituitary tumor: prolactin is secreted by the pituitary gland. If the pituitary gland enlarges and a pituitary prolactinoma occurs, it will lead to pituitary dysfunction and increased secretion of prolactin. (2) Idiopathic hyperprolactinemia: Since prolactin is a stress hormone, it may not be accompanied by pituitary-related disorders, and only leads to elevated prolactin after nerve stimulation. (3) Hypothyroidism: Hypothyroidism produces stimulation of the hypothalamus, leading to elevated thyrotropin, which is secreted by the pituitary gland, which secretes more prolactin when stimulated. The pituitary gland will secrete more prolactin when it is stimulated. There are many reasons for high pituitary prolactin, and it is necessary to go to the hospital for relevant examinations to make a clear diagnosis.