High prolactin in women: causes and what a high result means

High prolactin is called hyperprolactinemia. It is a finding with a long list of possible causes. Some are harmless or short-lived, and some need treatment. A clinician sorts them out. This page covers what a high result can mean, what usually happens next and when to get seen.

Prolactin

A single blood test for prolactin, a pituitary hormone linked to periods, fertility and milk production.

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What high prolactin does in women

MedlinePlus says higher-than-normal prolactin can affect how the ovaries work and cause menstrual problems and infertility. In people who are not pregnant or breastfeeding, it can also signal the body to make breast milk. Lab information adds that high prolactin can lead to missing periods, absent ovulation and decreased bone density.

Symptoms in women may include:

Irregular or absent periods
Breast milk when not pregnant or breastfeeding
Nipple discharge
Infertility

What can cause a high result

MedlinePlus lists these possible causes in people who are not pregnant or breastfeeding:

A prolactinoma. This benign tumor on the pituitary gland makes prolactin and is the most common cause.
Other pituitary disorders, including other pituitary tumors.
A disease of the hypothalamus, the part of the brain that controls the pituitary.
Hypothyroidism (an underactive thyroid).
Cirrhosis (scarring of the liver) or kidney disease.
PCOS. See PCOS tests.
Chest injuries.
Certain medicines. Lab information gives antipsychotic drugs and estrogen as examples. Never stop a medicine without talking to your clinician.

Not every high result points to a condition. MedlinePlus says diets high in protein and certain medicines can raise it, and that small increases can come from stress, exercise and even sex. Depending on your symptoms and history, a clinician may repeat the test to see whether the level stays high. The lab information adds that prolactin is released in episodes and follows a 24-hour cycle, so the result depends on when the sample was taken.

Prolactin is normally high in pregnancy and after birth, and stays raised while breastfeeding. If any of that applies to you, tell the clinician.

What happens next

MedlinePlus says that if your prolactin is high, your provider will usually order other blood tests to find the cause. If a prolactinoma is suspected, you may also have an MRI scan to look at the pituitary gland. Treatment depends on the cause. It is usually medicine, and surgery may be needed for certain pituitary tumors.

A prolactin test on its own cannot do any of this. The seller’s page says its prolactin order covers prolactin only, with no TSH, LH, FSH or other pituitary hormones. Thyroid tests, such as TSH, would be ordered separately.

How high is high?

“High” means above the range on your lab report. Ranges differ between labs and methods. A 2024 study from Amsterdam found that two prolactin immunoassays gave results 1.75 times apart on the same samples. See the prolactin test for a published female range and notes on preparing.

When to see a clinician

Take any result above the range on your report to a clinician. Be seen promptly if a high result comes with headaches or changes in vision. MedlinePlus says a prolactinoma that is not treated can grow large enough to press on the optic nerve and nearby parts of the pituitary gland.

Bring your cycle history, any breast symptoms and a list of everything you take, including vitamins.