Will my pituitary tumour affect breastfeeding?

A prolactinoma is a non-cancerous tumour in the pituitary gland, a small gland located under the brain that produces hormones. A prolactinoma can cause a range of problems, including headaches, changes in vision, and an increased level of the hormone prolactin. Increased prolactin can cause infertility and irregular periods among other symptoms. During pregnancy, the tumour is usually stable, but some women need treatment if it is growing or causing symptoms. If there are no symptoms, breastfeeding with a prolactinoma is considered safe. The tumour can be treated with medication or surgery, but both can decrease a mother’s ability to produce milk.

A) Describing prolactinomas

A prolactinoma is a benign (non-cancerous) tumour in the pituitary gland caused by overgrowth of the cells that make prolactin. Prolactinomas are most frequently found in women between 20 and 50 years of age. Prolactinomas can cause problems in two ways: (1) by direct effects on the brain as they grow in size; and (2) by creating abnormally high levels of prolactin.

 The effects on the brain can include:

  • Headaches
  • Changes in vision
  • Low levels of other hormones

Problems caused by high levels of prolactin can include:

  • Infertility
  • Irregular periods
  • Breast milk production outside of pregnancy and delivery
  • Breast enlargement
  • Acne and excessive body and facial hair
  • Fragile bones (low bone density)
  • Loss of sexual interest
  • Vaginal dryness

During pregnancy, the tumour is usually stable, but some women need treatment if it is growing or causing symptoms. Several studies have shown that pregnancy seems to have a beneficial effect on prolactinomas, with some mothers having normal prolactin levels after delivery whether they breastfeed or not (Cocks Eschler 2017).

B) Breastfeeding with a prolactinoma

If a mother is otherwise well, breastfeeding with a prolactinoma is safe. If it is causing symptoms, it may need treatment with medication or surgery.

Medication works to block the secretion of prolactin. The two best-known medications are bromocriptine and cabergoline. Neither is recommended for use during breastfeeding as they can decrease the amount of milk a mother makes.

Mothers who have had surgery to remove a prolactinoma risk having a permanently low milk supply, as the pituitary gland may have been damaged (Cocks Eschler 2017). Their babies should be watched closely to make sure they take in enough milk.

Some mothers use medication, such as domperidone or metoclopramide, to increase their milk supply. If you have a prolactinoma, please speak with your doctor before starting either one, as it may stimulate the growth of the prolactinoma.


Cocks Eschler D, Javanmard P, Cox K, et al. Prolactinoma through the female life cycle. Endocrine. 2017 Nov 24