Serum prolactin is a polypeptide hormone secreted by the prolactinizing cells of the pituitary gland, and there are usually both physiologic and pathologic factors that contribute to an increase in this value. Serum prolactin promotes the synthesis of milk, so during pregnancy and lactation, prolactin will be physiologically increased. Starting from about 7 weeks of pregnancy, it gradually rises and reaches a peak of about 150ug/L at full-term delivery, which is 10 times higher than that of non-pregnant women. However, in addition to the physiological increase, there are some pathological factors, such as pituitary adenoma, because prolactin is secreted by the pituitary gland, pituitary adenoma may make prolactin increase; and thyrotropin-releasing hormone can stimulate the secretion of prolactin, so when the thyrotropin-releasing hormone secretion of excessive, such as hypothyroidism and other diseases, it may make prolactin increase. If prolactin abnormality occurs, it is recommended to consult a doctor in time.