1. Menstrual Symptoms in Women
Prolactin is a hormone that is primarily involved in milk production and breast development. After you have a baby, your prolactin levels rise and cause your mammary glands to lactate, so you can breastfeed. Hyperprolactinemia is a condition characterized by high prolactin levels not related to pregnancy. If you have high prolactin levels in your body and you are female, your main symptom will probably be related to your menstrual cycle. Most women with hyperprolactinemia have some disruption to their cycles. This may show up as irregular periods, abnormal flow or loss of menstruation altogether (amenorrhea).
2. Non-postpartum Lactation
Galactorrhea is the term used for sudden production and flow of breast milk that does not follow pregnancy. This is a common symptom of high prolactin levels in premenopausal women but is less common in postmenopausal women because of their lack of estrogen. The elevated amount of prolactin in the body triggers the same response from the mammary glands as it would after you have a baby. In rare cases, this can also occur in males.
3. Sexual Dysfunction and Infertility
Besides milk production, prolactin is also associated with sexual desire and function. Regardless of your sex, if you have elevated prolactin levels, you will probably experience a loss of sexual libido. Men may become impotent, and women can start to experience pain from intercourse due to vaginal dryness. Additionally, infertility is a common symptom for both men and women. High levels of prolactin suppress the production of two key hormones, follicle-stimulating hormone (FSH) and gonadotropic-releasing hormone (GnRH), which are essential in fertility. This effect is why some women use breastfeeding as a form of birth control.
4. Tumor-Related Symptoms
High prolactin levels can be caused by a tumor on the pituitary gland in the brain. This is typically a pituitary adenoma (prolactinoma). If this is the cause of your hyperprolactinemia and the tumor is large in size, you may experience some symptoms related to pressure from the tumor on the surrounding areas, including the optic nerve. These symptoms are usually headaches and visual problems. Most prolactinomas are small in size and do not produce these symptoms. In some men, however, this is the only way they identify that they have a problem because they do not get menstrual symptoms and other symptoms are often overlooked.