This form of lactation is called galactorrhea. Galactorrhea is unrelated to the milk that a woman produces when breastfeeding.
People may worry about unexpected nipple discharge, but there is no link between galactorrhea and breast cancer.
In this article, learn about the possible causes of lactating without being pregnant or breastfeeding, as well as when to see a doctor.
Causes of lactation without being pregnant
Unexpected nipple discharge may have several potential causes.
The hormone prolactin causes lactation during pregnancy and while breastfeeding. People who have galactorrhea may produce too much prolactin.
The pituitary gland, which is a small gland at the base of the brain, makes and regulates prolactin and several other hormones.
Problems with the pituitary gland, such as a noncancerous tumor or another pituitary disorder, can sometimes cause people who are not pregnant to lactate.
Other causes of galactorrhea include:
- excessive breast and nipple stimulation
- medications, including antipsychotics, antidepressants, and drugs for high blood pressure
- an underactive thyroid
- chronic kidney disease
- nerve damage to the chest from an injury or surgery
- some types of hormonal birth control
- spinal cord surgery or injury
- use of marijuana, opioids, or cocaine
- some herbal supplements, including fenugreek, anise, or fennel
- testosterone deficiency in men
- high levels of estrogen in newborns
In rare cases, people may lactate due to an emotional response to an unrelated baby. One study described a young woman with type 1 diabetes whose nipples produced milky discharge under gentle pressure when she was near an unrelated newborn.
Her symptoms went away when she was no longer near the baby. Doctors ruled out all possible biological causes for lactation. In this case, researchers believe that her lactation was due to an emotional response to the baby.
Sometimes, doctors cannot pinpoint the underlying cause of galactorrhea. In these cases, the condition is called idiopathic galactorrhea.
People with idiopathic galactorrhea might have breasts that are overly sensitive to prolactin, meaning that even normal levels of the hormone might trigger them to produce a milky discharge.
Galactorrhea can cause headaches and breast tenderness.
The signs and symptoms of galactorrhea may vary depending on the underlying cause, but they typically include:
- persistent or sporadic milky discharge from the nipple on one or both breasts
- leaking from the nipples, either spontaneously or due to manual stimulation
- irregular periods
- headaches or visual disturbances
Men with galactorrhea may also experience the following symptoms:
- enlarged breast area around the nipples
- tenderness in the breast area
- erectile dysfunction
- loss of sexual desire
Diagnosing the cause of lactation when a person is not pregnant or breastfeeding can be challenging.
During the examination, the doctor will take a medical history and review any medications that the individual is taking.
They may also order other tests, including:
- a pregnancy test
- blood tests to check the levels of prolactin and thyroid-stimulating hormone (TSH)
- laboratory analysis of the breast milk to check for fat cells and confirm galactorrhea
- an MRI scan of the brain to check the pituitary gland, particularly if blood tests reveal elevated prolactin levels
- an ultrasound or mammogram of the breasts
A doctor may recommend changing medications to treat galactorrhea.
Treatment for galactorrhea depends on the underlying cause. Not all cases of galactorrhea will need treating.
In some cases, people can manage the symptoms with lifestyle modifications, such as minimizing nipple stimulation, avoiding tight clothing, and wearing padded inserts inside a bra to soak up any discharge.
Where treatment is necessary, it will center on resolving the underlying cause of lactation. Treatment may include:
- changing medications
- treating an underactive thyroid with a thyroid-stimulating medicine
- surgical removal of any tumors affecting the pituitary gland
- testosterone replacement therapy
A person should never change medications without talking to a doctor first. A doctor will be able to recommend replacements and monitor any potential side effects.
Lactating while not pregnant or breastfeeding is called galactorrhea. It has a variety of causes and associated symptoms.
Not all causes of galactorrhea are serious, but diagnosis can occasionally be challenging. Anyone experiencing symptoms of galactorrhea should speak to a doctor.