Prolactin level is generally not more than 20ng/ml, more than the normal value range may lead to no menstruation, the specific value is not standardized, individual differences are relatively large. The moderate secretion of prolactin can make the body’s endocrine system maintain balance, so that women have normal menstruation and ovulation, pregnancy and other phenomena. Elevated levels of prolactin can lead to abnormalities in gonadotropins, which can prevent follicles from developing and maturing normally, resulting in irregular or absent periods. Elevated prolactin levels are often caused by medications or diseases, such as oral domperidone tablets, cimetidine tablets, birth control pills, etc. Diseases such as pituitary tumors, renal failure, hypothyroidism, polycystic ovary syndrome and other illnesses can lead to elevated levels of prolactin, resulting in the absence of menstruation. When women do not have menstruation, they should consult a doctor to find out the cause of the disease and actively carry out treatment.