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Leaking breasts when pregnant

Many expectant women, particularly during the third trimester, will notice their breasts leaking a yellowish milky substance called colostrum, which will make up a baby’s first few meals. It is higher in protein and lower in fat than regular breast milk, and contains antibodies that will help the immune system develop outside of the womb.

What causes it?

As your pregnancy draws to a close, your body needs to make sure that all of its systems are up and running prior to delivery. Colostrum is the substance that will make up a baby’s first meals, so leaky breasts are simply your body’s way of checking that milk production will be all set to go when it needs to be.


There is nothing you can do to stop leaking colostrum, but because generally only a few drops seep out, this is an easier symptom to manage than most. If you are concerned about colostrum in your shirt, simply wear a nursing pad in your bra, and avoid wearing any tops you might dread seeing stained. To avoid making the leakage worse, you should avoid nipple stimulation. You should also let your healthcare provider know if the fluid is bloody, or greenish in color.

Reviewed by Dr. Jamie Lo
Read more
  • Laura M’Rabet, Arjen Paul Vos, Gunther Boehm, Johan Garssen. “Breast-Feeding and Its Role in Early Development of the Immune System in Infants: Consequences for Health Later in Life.” Journal of Nutrition. vol. 138 no. 9 1782S-1790S. Web. 9/8/2015.
  • “Colostrum: Your Baby’s First Meal.” HealthyChildren. American Academy of Pediatrics, 8/20/2015. Web.
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