Hyperprolactinemia (High prolactin levels)

Hyperprolactinemia means that you have high levels of the hormone prolactin. Prolactin is a reproductive hormone produced by the pituitary gland which spikes during pregnancy and causes the breasts to produce milk after childbirth. 

This article has been verified by a medical professional

Your pituitary gland is a pea-sized gland at the base of your brain, around eye level. Although it’s very small, it plays an essential role in your endocrine system and affects almost every part of your body.

Elevated prolactin is a very common hormonal imbalance, affecting around 1 in 3 women with irregular periods but normal ovaries. 

Impact of hyperprolactinemia on fertility

High levels of prolactin reduce ovarian function, leading to something called normogonadotropic hyperprolactinemic ovarian insufficiency. Ovarian insufficiency means that the ovaries aren’t working as they should, causing problems with egg maturation and ovulation. 

This happens because elevated prolactin levels prevent the pituitary gland from releasing follicle-stimulating hormone, which is the one responsible for maturing your eggs each cycle. It can also interfere with the production of other important reproductive hormones, including estrogen and progesterone. As a result, women with excess prolactin don’t ovulate regularly and may experience luteal phase deficiency. In luteal phase deficiency, the uterine lining doesn’t thicken as it should, making it difficult for a fertilized egg to implant in the womb. Because of this, getting pregnant becomes quite challenging.

Potential causes of hyperprolactinemia

Common causes of hyperprolactinemia include:

• Benign tumors on the pituitary gland (prolactinomas)
• Underactive thyroid (hypothyroidism) – about half of all women with hyperprolactinemia have a thyroid disorder
• Kidney condition
• Medicines for depression, psychosis, and high blood pressure
• Certain herbs, such as fenugreek, fennel seeds, and red clover
• Chest wall irritation (from scarring after surgery, shingles, or a bra that’s too tight)
• Excessive stress or exercise
• Lack of sleep
• Some foods

Medical experts are unsure what causes a prolactinoma to form. A rare genetic disorder called multiple endocrine neoplasia, type 1, can increase the risk of getting a prolactinoma.

Symptoms of hyperprolactinemia

These are potential symptoms of hyperprolactinemia in women:

• Irregular or missed periods (amenorrhea)
• Milky discharge from the nipples when not pregnant or breastfeeding
• Vaginal dryness and painful sex
• Infertility 
• Weak, brittle bones
• Vision problems
• Headache

Diagnosis of hyperprolactinemia

Doctors diagnose hyperprolactinemia based on a person’s symptoms, medical history, and a test that measures the level of prolactin in the blood. Because some factors, including stress, sleep deprivation, exercise, and medication, can affect the prolactin measurement, it may be tested again to confirm the high level and diagnose hyperprolactinemia. 

When the blood tests show highly elevated prolactin, doctors may order an MRI scan of the brain to check for prolactinoma. You may be also referred to an eye doctor (ophthalmologist) if you’re experiencing vision problems. Finally, you may be referred to a specialist in hormonal disorders (endocrinologist) for further testing and treatment.

Treatment to improve fertility

The good news is that hyperprolactinemia is just a temporary cause of infertility. In most cases, hyperprolactinemia responds quite well to treatment. 

Depending on what’s causing your body to make extra prolactin, treatment can include:

• Medication to reduce prolactin levels. Dopamine agonists are usually prescribed as the first line of treatment for women trying to conceive, and are very effective at making the ovaries function normally again.  
• Switching from (or reducing the dose of) medication that’s causing elevated prolactin.
• Medication to shrink prolactinoma(s). Very rarely, surgery or radiation is needed if medication is unsuccessful. 
• Treatment for hypothyroidism. 

Once treatment helps get prolactin back to a normal level, the ovaries will work normally again and periods and ovulation will return, along with fertility.

This article has been verified by a medical professional

• Hyperprolactinemia (High Prolactin Levels). ReproductiveFacts.org from the American Society for Reproductive Medicine. Accessed 07 July 2022.
• Kaiser UB, MD: Hyperprolactinemia and infertility: new insights. J Clin Invest. 2012;122(10):3467-3468.
• What is Hyperprolactinemia and How Can It Affect Getting Pregnant? What to expect. Accessed 07 July 2022.
• Crosignani PG: Management of hyperprolactinemic infertility. Middle East Fertility Society Journal. 2012;17(2):63-69. 
• Prolactinoma. Mayo Clinic. Accessed 07 July 2022.
• Domingue ME et al.: Outcome of prolactinoma after pregnancy and lactation: a study on 73 patients. Clin Endocrinol (Oxf). 2014;80(5):642-8.
• Patient education: High prolactin levels and prolactinomas (Beyond the Basics). UpToDate. Accessed 02 September 2022.
• Hyperprolactinemia. Yale Medicine. Accessed 29 December 2022.
• World Health Organization classification of anovulation. UpToDate. Accessed 14 December 2022.
• What is Hyperprolactinemia and How Can It Affect Getting Pregnant? What to expect. Accessed 07 July 2022.
• Prolactinoma – Symptoms & causes. Mayo Clinic. Accessed 08 December 2022.
• Prolactinoma – Diagnosis & treatment. Mayo Clinic. Accessed 08 December 2022.
• Pituitary Gland. Cleveland Clinic. Accessed 08 December 2022.