What is the cause of galactorrhea (spontaneous milk production)?

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Last updated: March 5, 2025 • View editorial policy

From the Guidelines

Galactorrhea is primarily caused by elevated prolactin levels, which can result from various factors including pituitary tumors, hypothyroidism, medications, and idiopathic causes. The condition is characterized by the abnormal production of breast milk in men or women who are not breastfeeding. According to the most recent evidence [ 1 ], it is essential to assess baseline macroprolactin levels where serum prolactin is found to be mildly or incidentally elevated. Some key points to consider in the diagnosis and management of galactorrhea include:

  • Elevated prolactin levels can be caused by medications, pituitary tumors, hypothyroidism, chest wall stimulation, or idiopathic causes [ 2 ].
  • Management begins with identifying and addressing the underlying cause [ 1 ].
  • If medication-induced, consider switching to an alternative drug with your doctor's guidance.
  • For prolactinomas (pituitary tumors), dopamine agonists like cabergoline or bromocriptine are the first-line treatments [ 1 ].
  • Evaluation typically includes a thorough medication review, prolactin level measurement, thyroid function tests, and possibly pituitary MRI if prolactin is significantly elevated [ 1 ]. It is crucial to note that while often benign, galactorrhea warrants medical attention to rule out serious underlying conditions like pituitary tumors that could affect vision or fertility if left untreated [ 1 ].

From the Research

Causes of Galactorrhea

  • Galactorrhea is commonly caused by hyperprolactinemia, especially when it is associated with amenorrhea 3
  • Hyperprolactinemia is most often induced by medication or associated with pituitary adenomas or other sellar or suprasellar lesions 3, 4
  • Less common causes of galactorrhea include: + Hypothyroidism 3, 5 + Renal insufficiency 3, 5 + Pregnancy 3, 5 + Nipple stimulation 3 + Chronic renal failure 5 + Cirrhosis 5 + Pituitary macroadenomas 5 + Hypothalamic lesions 5 + Unidentifiable causes 5

Evaluation and Diagnosis

  • A pregnancy test should be obtained for premenopausal women who present with galactorrhea 5, 6
  • In addition to prolactin and thyroid-stimulating hormone levels, renal function should also be assessed 5
  • Medications contributing to hyperprolactinemia should be discontinued if possible 3, 5
  • Magnetic resonance imaging of the pituitary gland should be performed if the cause of hyperprolactinemia is unclear after a medication review and laboratory evaluation 3, 5

Treatment Options

  • Treatment of galactorrhea is not needed if prolactin and thyroid-stimulating hormone levels are normal and the discharge is not troublesome to the patient 3, 5
  • Cabergoline is the preferred medication for treatment of hyperprolactinemia 5, 7
  • Dopamine agonists (bromocriptine, pergolide, cabergoline) are extremely effective in lowering serum prolactin, restoring gonadal function, decreasing tumor size, and improving visual fields 4, 7
  • Transsphenoidal surgery may be necessary if prolactin levels do not improve and symptoms persist despite high doses of cabergoline and in patients who cannot tolerate dopamine agonist therapy 5, 7

References

Guideline

reproductive dysfunction in women with epilepsy: recommendations for evaluation and management.

Journal of Neurology, Neurosurgery and Psychiatry, 2002

Research

Evaluation and management of galactorrhea.

American family physician, 2012

Research

Guidelines for the diagnosis and treatment of hyperprolactinemia.

The Journal of reproductive medicine, 1999

Research

Galactorrhea: Rapid Evidence Review.

American family physician, 2022

Research

Evaluation and treatment of galactorrhea.

American family physician, 2001

Research

Hyperprolactinemia.

International journal of fertility and women's medicine, 1999

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.