How Your Body Makes Milk

When your baby sucks during breastfeeding, it sends a message to your brain. This message releases oxytocin and prolactin. These are the hormones that tell your body to release and make more milk. As your milk is being removed through breastfeeding, the cycle starts over again.

Did you know that your breast size does not determine how much milk you will make? Your milk is produced in milk-making glands inside your breasts called alveoli. When your baby breastfeeds, milk is released into the milk ducts with the help of tiny muscles contracting which is called a letdown reflex. The milk then travels through the milk ducts and out through your nipple openings. This may sound confusing. 

Think of your milk-making glands as a bunch of grapes. The alveoli that make the milk are the grapes. The milk ducts that the milk travels through are the stems of the grapes. If your breasts became full and tender during pregnancy this was a sign that the alveoli were getting ready to make milk. Not every lactating woman notices this change.

A letdown reflex is a conditioned reflex where tiny muscles contract around the alveoli (the grapes) to squeeze the milk out through the nipple openings. This letdown reflex can happen anywhere from a few seconds or a few minutes of your baby starting to suckle at your breast. 

Some women experience one let down in a breastfeeding session and others have multiple let downs during a breastfeeding session. Some women feel a tingling or uncomfortable sensation when this occurs. 

If you do not feel any of these sensations, another way to tell if you are having a letdown is by observing the baby. Since milk is flowing faster, you may hear the baby swallow more frequently or take “gulps” of milk. Some women can also have a letdown reflex triggered by things other than their baby nursing. This can include their baby crying, thinking about your baby, the smell of your baby, or seeing other babies.

If you are pregnant and would like more information about breastfeeding call The Care Connection to sign up for our Breastfeeding 101 class!

Written By: Christie Davis, RN, IBCLC

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