What Is Prolactin?

This hormone helps regulate the menstrual cycle in women and sperm production in men.

Prolactin is a hormone produced by the pituitary gland, which is located near the bottom of the brain.

Its production is controlled by other hormones called prolactin-inhibiting factors, which include dopamine.

Both men and women tend to have small amounts of prolactin in their blood.

In men, prolactin encourages the production of sperm.

In women, prolactin helps regulate the menstrual cycle and causes breasts to grow and develop.

When a woman is pregnant, her levels of prolactin go up. Once the baby is born, elevated prolactin levels cause the production of milk for breastfeeding.

What Is Hyperprolactinemia?

If women or men have too much prolactin in their blood, they may have a condition called hyperprolactinemia.

High levels of prolactin can interfere with the normal production of hormones, such as estrogen and progesterone.

According to the American Society for Reproductive Medicine (ASRM), a third of women in their childbearing years with irregular menstrual periods but normal ovaries have hyperprolactinemia.

Women with hyperprolactinemia can still take birth control pills to avoid pregnancy or to regulate their menstrual cycle.

While some women have high prolactin levels with no symptoms, others may experience:

• Trouble getting pregnant
• Breast milk production, despite not being pregnant
• A change or stop in ovulation, due to changes in the production of hormones estrogen and progesterone
• Irregular or absent menstrual missed periods

In men, high prolactin levels can cause:

• Milky discharge from nipples
• Inability to get an erection
• Reduced desire for sex
• Infertility
• Low production or no production of sperm

If you experience any of the above, your doctor can check your levels of prolactin by ordering a blood test.

High levels of prolactin may also indicate the following conditions:

• Chest wall trauma or irritation, caused by surgical scars, shingles, or other factors
• Hypothalamic disease (a problem with the hypothalamus, a region of the brain)
• Hypothyroidism (underactive thyroid)
• Kidney disease
• A prolactinoma, a pituitary gland tumor that produces prolactin (most commonly diagnosed in women under age 50)
• Other pituitary tumors and diseases

While no cause is found in about one-third of all cases of hyperprolactinemia, according to the ASRM, the condition may also be caused by:

• Certain medications to treat depression, psychosis, or high blood pressure
• Herbs, such as fenugreek, fennel seeds, and red clover
• Excessive stress or intense exercise
• Certain foods
• Nipple stimulation

Treating Prolactin Levels

Talk with your doctor about your options for treating a prolactin deficiency or high levels of prolactin.

If your doctor can't find the cause of your irregular levels of prolactin, or if high prolactin levels are due to a small tumor in the pituitary gland and you're still producing estrogen, no treatment may be needed.

In some cases, though, medications or surgery may be able to help your condition, depending on the exact cause of your abnormal prolactin levels.

The most commonly used medicines are cabergoline and bromocriptine, which are usually taken until your prolactin levels return to normal or until you become pregnant, if that's your goal.

If you have a large pituitary tumor that's causing your high prolactin levels and medication has not improved your symptoms, your doctor may recommend surgery to remove the tumor.