High prolactin (hyperprolactinaemia)

Periods that stop and milk-like nipple discharge can be signs of raised prolactin. Prolactin is made by the pituitary gland at the base of the brain and helps stimulate breast milk production. It rises during pregnancy and breastfeeding. If your level is raised outside pregnancy or breastfeeding, a clinician will need to look at what else could explain it.

Why it can affect periods

High prolactin can interfere with the hormone signals that support ovarian function, lowering oestrogen and affecting fertility. Symptoms can include irregular or absent periods, reduced interest in sex and vaginal dryness. Lower sex-hormone levels can also contribute to bone loss.

Not everyone with high prolactin has nipple discharge, so the condition is still possible without it. Discharge can also have other causes and needs an assessment of its own.

A raised result does not always mean a tumour

Some medicines can raise prolactin, including certain antipsychotics, medicines for nausea and vomiting, some blood-pressure medicines and opioid painkillers. An underactive thyroid or kidney disease can also raise prolactin. Bring a complete medicine list to your appointment, including medicines prescribed by another service.

A prolactinoma is a non-cancerous tumour in the pituitary gland that makes prolactin. Other growths near the pituitary can also raise the level. Larger prolactinomas can press on nearby structures, causing headaches or vision problems. Sometimes no cause for raised prolactin is found.

Temporary rises can follow exercise, stress from a blood draw or nipple stimulation. A clinician may repeat a mildly raised result before deciding what it means. Ask how to prepare for the repeat test; do not try to interpret a single result from an online range.

What the tests look for

Your clinician will start with a prolactin blood test and ask about your medicines and health history. Further tests can check thyroid function, exclude pregnancy and sometimes look for macroprolactin, a form that does not cause health problems. If a pituitary tumour is suspected, an MRI scan can show its size and location.

Treatment depends on the cause and your priorities

Some people with raised prolactin and few or no symptoms do not need treatment. If a medicine is contributing, the prescriber can discuss alternatives. Do not stop or change a prescribed medicine without talking to your doctor, including medicines used for mental health.

Prolactinomas are commonly treated with dopamine agonist medicines, such as cabergoline or bromocriptine, which reduce prolactin and can shrink the tumour. Surgery is another option when medicines are unsuitable or do not work; radiotherapy is used more rarely. Your specialist or pharmacist can advise about prescribed treatment.

Tell your specialist if you want to become pregnant or find out that you are pregnant. Treatment can restore fertility, and pregnancy needs a separate medicine and monitoring plan. Ask what to do when a pregnancy test is positive and who to contact about symptoms while waiting for an appointment.

If a prolactinoma is confirmed, the doctor may check other pituitary hormones and arrange a vision test, depending on the tumour’s size. At follow-up appointments, your doctor will consider your symptoms and the tumour’s effects alongside the prolactin result. Ask which changes to report between appointments and how to reach the team.

Headache and vision changes: where to get help

Call 999 now in the UK or 911 in the US, or your local emergency number, if a headache starts suddenly and is extremely painful, or you have a headache with loss of vision. For a headache with new vision or eye problems, contact an urgent GP service or NHS 111 today in the UK, or your doctor or urgent care service elsewhere. Emergency symptoms take priority over a routine hormone appointment.

Book a routine GP or doctor appointment for nipple discharge or periods that stop or become irregular. Describe when the changes began and bring the names of your medicines. Ask what your doctor is checking for and when your next review will be.