Increased prolactin levels, also known clinically as hyperprolactinemia, are caused by a variety of reasons that increase the level of prolactin in the blood, resulting in a series of clinical symptoms. In women, increased prolactin often leads to menstrual abnormalities, menstrual cycle disorders, or heavy or light menstrual flow. Infertility may occur in some women, and osteoporosis or even pathologic fractures may occur if the disease is prolonged. In male patients, hyperprolactinemia often leads to hypogonadism, and if accompanied by pituitary macroadenomas, there will be symptoms of tumor compression, such as vision loss, headache and dizziness.