- Low Levels
- High Levels
- When to See the Doctor
What are prolactin levels?
Prolactin, or milk hormone, is the hormone that causes breasts to grow. It is produced by the pituitary gland located at the bottom of the brains of both men and women. Prolactin is also responsible for the creation of breastmilk after a baby is born and 300 other functions.
When there is too much prolactin in the blood of a man or woman who is not pregnant, it is called hyperprolactinemia. People who have this condition amount to a third of all women in their childbearing years. Although these women have healthy ovaries (the reproductive organs that carry a woman’s eggs/ova) they experience irregular periods.
A person with low prolactin levels is said to have hyperprolactinemia, or prolactin deficiency. Lower levels of prolactin usually do not need medical treatment.
Symptoms of low and high prolactin levels
Women who have low levels of prolactin in the blood may experience the following:
Although some people who have high prolactin levels don’t show any signs and symptoms, both men and women may have difficulty having children and decreased desire for sex.
Other signs and symptoms include:
- Erectile dysfunction—trouble getting or keeping an erection
- Breast enlargement, also called gynecomastia
- Decreased muscle mass and body hair
- Vaginal dryness, leading to pain during intercourse
- Problems with menstruation—having no periods or irregular periods
- Production of breast milk when not pregnant or nursing
Women with high prolactin levels may also experience galactorrhea. A woman who has this condition may find it difficult to get pregnant. Her breasts may also start producing milk while she is not pregnant. Ninety percent of women with galactorrhea also have hyperprolactinemia.
Causes of low levels of prolactin
There may be a number of causes of low levels of prolactin, including the following.
A condition that causes an inability to breastfeed.
There is evidence that the reduction of breast milk in women who smoke cigarettes may be linked to an effect of nicotine on the production of prolactin.
Retained placental fragments
The placenta contains hormones that are known to decrease prolactin levels.
Causes of high levels of prolactin
Prolactinoma (pituitary tumor)
A non-cancerous growth or tumor on the pituitary gland. The tumor can be large or small, and it produces high levels of prolactin. Prolactinomas occur more in women than in men but rarely in children.
Hypothyroidism or underactive thyroid
If you have this condition, your thyroid gland does not produce enough thyroid hormone.
Some other common causes are:
- Medicines given for depression, psychosis, and high blood pressure
- Herbs, including fenugreek, fennel seeds, and red clover
- Irritation of the chest wall (from surgical scars, shingles, or even a too-tight bra)
- Stress or exercise (usually excessive or extreme)
- Certain foods
- Nipple stimulation
- Birth control pills
When to see your doctor about prolactin
A prolactin test measures the level of prolactin in your blood. The following are indications that you should talk to your doctor about doing a PRL.
If you are a woman:
- Production of breast milk if you are not pregnant or breastfeeding
- Nipple discharge
- Changes in vision
- Irregular periods
- Periods that have stopped completely before the age of 40, known as premature menopause
- Breast tenderness
If you are a man:
Diagnosis and tests for low and high prolactin levels
Apart from the prolactin levels test, your doctor may conduct blood tests to measure levels of prolactin. If you just had a meal or are stressed, your prolactin levels might show up higher. In such a case, your doctor will have you fast and relax, then repeat the test.
Doctors will also ask about other conditions and medication use, and rule out pregnancy. Other advanced tests may include a scan of your brain through magnetic resonance imaging (MRI) to check for a tumor of the pituitary gland.
Treatment for high levels of prolactin
Your doctor will treat you according to the cause of the condition. Usually, your doctor will prescribe thyroid replacement medicine to bring your prolactin levels back to normal. If a medicine is the cause, your doctor will help you find something to get your levels back to normal. If a cause was not found, there is no need to get treated for the condition.
A woman with hyperprolactinemia may continue taking birth control pills to prevent pregnancy or make their periods regular. However, women who cannot create estrogen due to high levels of prolactin should get treated.
Endocrinology & Metabolic Syndrome: "The Role of Prolactin in Men."
Hormone Health Network: "Hyperprolactinemia."
The National Institute of Diabetes and Digestive and Kidney Diseases: "Hypothyroidism (Underactive Thyroid)."
Penn Medicine: "Prolactinoma."
Medscape: "Prolactin Deficiency."
Medscape: "Prolactin Deficiency Clinical Presentation."
Trends in Endocrinology & Metabolism: "The endocrine effects of nicotine and cigarette smoke."
U.S. National Library of Medicine: "Prolactin Levels."
You and Your Hormones: "Prolactin."
Top What Causes Low and High Prolactin Levels Related Articles
Can Hormonal Imbalance Affect Pregnancy?Hormonal imbalance is a common issue that affects many people. Learn the signs of hormonal imbalance, how it affects pregnancy, how doctors diagnose it, and what you can do to treat it.
What Are the Causes and Symptoms of Hormonal Imbalances in Women?The main causes of hormonal imbalances are issues with the thyroid, stress, and eating disorders. Some symptoms include irregular periods, low sex-drive, unexplained weight gain, and mood swings. Getting rid of hormonal belly fat involves treating the underlying cause along with diet changes, regular exercise, and stress management.
Erectile Dysfunction (ED, Impotence)Erectile dysfunction (ED, impotence) is the failure to achieve or maintain an erection. There are many potential underlying causes of erectile dysfunction, including stress and emotional problems, brain dysfunction, problems with blood supply to the penis, and structural problems with the penis.
Gynecomastia (Enlarged Male Breasts)Gynecomastia, an enlargement of the gland tissue in the male breast is caused by an imbalance of hormones. Check out the center below for more medical references on gynecomastia, including multimedia (slideshows, images, and quizzes), related disease conditions, treatment and diagnosis, medications, and prevention or wellness.
How Can a Man Tell if He Has a Hormonal Imbalance?What is a hormonal imbalance? Learn the signs of hormonal imbalance in men and what to do if you suspect you have a hormonal imbalance.
Hyperthyroidism is an excess of thyroid hormone due to an overactive thyroid gland. Symptoms can include increased heart rate, weight loss, heart palpitations, frequent bowel movements, depression, fatigue, fine or brittle hair, sleep problems, thinning skin, and irregular vaginal bleeding.
Graves' disease is the most common cause of hyperthyroidism. Many other health problems or taking excess thyroid hormone medication can cause an overactive thyroid gland. Treatment for the condition is with medication, radioactive iodine, thyroid surgery (rarely), or reducing the dose of thyroid hormone. No diet has been shown to treat hyperthyroidism or its symptoms and signs.
Hyperthyroidism: Symptoms, Treatment, MedicationWhat are the symptoms of hyperthyroidism? What causes hyperthyroidism? What happens when you take thyroid medication? Hyperthyroidism occurs when an overactive thyroid gland produces an excessive amount of thyroid hormone. Learn hyperthyroidism causes, symptoms, and treatment.
HypothyroidismHypothyroidism is any state in which thyroid hormone production is below normal. Normally, the rate of thyroid hormone production is controlled by the brain by the pituitary gland. Hypothyroidism is a very common condition and the symptoms of hypothyroidism are often subtle but may include constipation, memory loss, hair loss, and depression. There are a variety of causes of hypothyroidism, and treatment depends on the cause.
Impotence QuizDid you know that certain medical condition may be responsible for ED? Some causes of impotence are medically treatable and reversible. Learn more about what can be done about erectile dysfunction with the Impotence Quiz.
Impotence SlideshowHaving erection problems? What is erectile dysfunction (ED)? Learn about erectile dysfunction causes and treatments such as drugs (pills), pumps, and more.
Ovulation & FertilityBoost fertility and increase your chances to conceive. Learn about ovulation calendars, diet, aging and other factors that can affect pregnancy.
PubertyThe time when boys and girls begin the process of sexual maturation is called puberty. During this time, both sexes undergo a series of biological changes that include a rapid increase in height, bone growth, weight increase, the growth of pubic hair, breast development, and the onset of menstruation in girls, and testicle, penis, and muscle enlargement in boys.
Puberty in Girls QuizTake the Puberty In Girls Quiz to learn the myths and facts about normal adolescent growth and development for teens and tweens.
Your Thyroid: Common Thyroid Problems and Diseases ExplainedLearn about thyroid problems such as hyperthyroidism, hypothyroidism, thyroid cancer, and more. Discover symptoms and treatments for various thyroid problems.
Vaginal Dryness and Vaginal AtrophyVaginal dryness and vaginal atrophy occurs in women during perimenopause, menopause, and postmenopause. With vaginal atrophy, the lining of the vaginal wall becomes thinner, drier, less elastic, and light pink to bluish in color. Symptoms of vaginal atrophy include vaginal dryness, itching, irritation, and/or pain during intercourse. Treatment options for vaginal dryness and vaginal atrophy include hormone treatment and over-the-counter vaginal lubricating and moisturizing products.
What Is the Normal Cycle for Menstruation?A normal menstrual cycle typically lasts about 28 days long. Check out the center below for more medical references on menstruation, including multimedia (slideshows, images, and quizzes), related disease conditions, treatment and diagnosis, medications, and prevention or wellness.