Prolactin has an immunomodulatory effect, if a woman is not pregnant or not lactating and has low prolactin, it may be a normal physiological manifestation, and if there are no other symptoms, treatment is generally not needed and regular review is sufficient; if the prolactin is low during pregnancy or lactation, it may be related to the following diseases: 1. pituitary or hypothalamus lesions: prolactin is a peptide hormone secreted by the pituitary gland, if the pituitary gland or hypothalamus has lesions such as hypopituitarism, it may lead to low prolactin; 2. If the pituitary gland or hypothalamus has a lesion such as hypopituitarism, it may lead to low prolactin; 2. Single prolactin deficiency: it may cause a decrease in prolactin secretion, resulting in low pituitary prolactin; 3. Hypothyroidism: it not only affects the secretion of thyroid hormone, but also leads to a decrease in prolactin secretion. 4. Other diseases: such as after ovariectomy, kidney cancer, non-functional pituitary adenoma, etc. diseases. Patients should go to the hospital in time to clarify the causes of low prolactin for symptomatic treatment to avoid delaying the condition.