Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the symptoms of Prolactinoma ?
    ### Response:
    In women, high levels of prolactin in the blood often cause infertility and changes in menstruation. In some women, periods may stop. In others, periods may become irregular or menstrual flow may change. Women who are not pregnant or nursing may begin producing breast milk.
    