Hyperprolactinemia is a condition in which a person has higher-than-normal levels of the hormone prolactin in the blood. The main function of prolactin is to stimulate breast milk production after childbirth, so high prolactin levels are normal in pregnancy. Prolactin also affects the levels of sex hormones (estrogen and testosterone) in both women and men. Prolactin is made by the pituitary gland, a pea-sized organ found at the base of the brain.
One common cause of hyperprolactinemia is a growth or tumor on the pituitary gland called a prolactinoma. The tumor produces high levels of prolactin. These tumors can be large or small and are usually benign, meaning they are not cancerous. Small tumors (smaller than 1 cm) are called mircoprolactinomas and larger tumors (more than 1 cm) are called macroprolactinomas. Large tumors can also cause headaches, vision problems, or both. Prolactinomas are more common in women than in men and rarely occur in children.
Certain prescription medicines can also increase prolactin levels. These include medicines for:
Other causes include:
Sometimes, no cause for hyperprolactinemia can be found.
Both men and women may have infertility, decreased sex drive, and bone loss. In addition, women may have:
Men may also have:
A blood test is used to detect excess prolactin. If prolactin levels are high, more tests are usually done to check blood levels of thyroid hormone. Normal thyroid hormone levels rule out hypothyroidism as a cause of hyperprolactinemia. Doctors will also ask about other conditions and medication use, and rule out pregnancy.
If a prolactinoma is suspected, an MRI (magnetic resonance imaging) of the brain and pituitary is often the next step. Using a special machine that creates images of body tissues, an MRI can reveal a pituitary tumor and show its size.
No, pituitary tissue lies outside the blood brain barrier and pituitary tumors are not considered to be brain tumors. These are almost always benign.
Treatment is based on the cause. Some people with high prolactin levels, but few or no signs and symptoms, do not need any treatment. Options for treating tumors include:
Hypothyroidism is treated with synthetic thyroid hormone, which should bring prolactin levels back to normal. If high prolactin levels are caused by prescription medications, other types of medications can be explored.
Most prolactinomas respond very well to medication and you should not have trouble conceiving once the levels normalize. The medications are usually stopped during the course of pregnancy.
The Hormone Health Network is the public education affiliate of the Endocrine Society dedicated to helping both patients and doctors find information on the prevention, treatment and cure of hormone-related conditions.
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