Understanding hyperprolactinaemia

What is hyperprolactinaemia?

• Prolactin is a hormone produced by the pituitary gland in the brain. Prolactin is released into the blood and is needed by the body to make breast milk following childbirth
   
• Hyperprolactinaemia is a medical condition that occurs when your body makes excessive amounts of the hormone prolactin
   
• Hyperprolactinaemia mostly affects young women before the menopause, but can also occur in women after the menopause and in men
   
• Hyperprolactinaemia can be treated with medication that reduces the amount of prolactin made

What causes hyperprolactinaemia?

• Hyperprolactinaemia can be caused by disorders of the pituitary gland, disorders of the thyroid gland (hypothyroidism) and certain types of medication
   
  • Benign growths of the pituitary gland called prolactinomas are the most common cause of hyperprolactinaemia (30–40% of cases)
     
• However, the cause of hyperprolactinaemia may be unknown in up to 40% of cases

What problems can hyperprolactinaemia cause?

• When your prolactin levels rise above normal you will experience similar effects to those seen after giving birth. These include:
   
  • Reduced function of the reproductive organs (ovaries and testes), known as hypogonadism, which women will experience as reduced menstruation (infrequent periods) or a complete absence of normal menstruation (no periods)
     
  • Infertility (in women and men)
     
  • Reduced interest in sex (decreased libido)
     
  • Bone loss (osteoporosis), which may lead to bone fractures
     
  • Increased production of breast milk (known as galactorrhoea), which may also occur in men on rare occasions
     
  • Male impotence

How is hyperprolactinaemia diagnosed?

• Your doctor will take a detailed medical history from you and carry out a clinical examination. A blood sample will be taken for biochemical tests (including measurement of prolactin levels, a pregnancy test and renal and thyroid function tests)
   
• Your doctor will usually take the blood sample from you in the morning, while you are fasting and resting, and during the first few days of your menstrual cycle if you are female
   
• Your doctor will try to find out whether your symptoms of hyperprolactinaemia are due to secondary causes, such as medication or hypothyroidism
   
• If such potential causes of hyperprolactinaemia cannot be identified, then imaging of the pituitary gland (preferably with an MRI scan) will be required to establish whether a growth or other abnormality is present
   
• Your doctor may follow-up your treatment by taking further blood samples to monitor the effects of your treatment on your prolactin levels