Prolactin

  • Prolactin is the hormone released from the anterior pituitary and stimulates the production of breast milk.

  • It has also been found to have many functions around the body, including metabolism, reproduction, regulation of fluids and the immune system.

  • The release of prolactin is affected by other hormones including dopamine, oestrogen, thyrotropin releasing hormone (see thyroid), oxytocin and anti-diuretic hormone (see posterior pituitary hormones).

  • Some women with Lymphocytic Hypophysitis release too much prolactin due to inflammation and significant enlargement of their pituitary. This is known as hyperprolactinaemia. This can result in unwanted breast milk production and disturbance to the menstrual cycle.

  • A deficiency in prolactin is known as hypoprolactinaemia and is caused by damage to the pituitary gland. This results in a lack of breast milk production following pregnancy. Lack of breast milk production is a key early sign of pituitary damage in the postpartum period.

Further reading at You & Your Hormones here.

Testing for prolactin

  • Your doctor may request a blood test to measure your prolactin.

 Medication for prolactin excess (hyperprolactinaemia)

  • Doctors may prescribe a medication called Cabergoline or Bromocriptine to reduce the amount of prolactin released. Your endocrinologist will advise you on this and whether this is right for you.

Medication for prolactin deficiency (hypoprolactinaemia)

  • For those with a deficiency of prolactin, there isn’t a hormone replacement medication.

  • Some women are prescribed medication such as Domperidone to increase their milk supply before their pituitary damage is detected.

  • Domperidone affects the levels of dopamine in the body and this change is detected by the hypothalamus. This would usually stimulate the pituitary to release more prolactin, causing milk supply to increase. If the cells in the pituitary gland are damaged, they can no longer be stimulated to release prolactin.

  • We need more health professionals in pregnancy, maternity, and post-partum services to be aware that lack of breast milk (or reduced breast milk supply) can be an early sign of pituitary damage.

  • Being unable to breastfeed can be a sad and frustrating experience. You can find more information here and join our community to find understanding and support here.