Many expectant mothers I have counseled would tell me they were planning to breastfeed, only for them to return after the baby was born exclaiming that they never had any milk and had to give the baby formula. This occurrence happened frequently. Because we are mammals, our bodies will produce milk. This is what breasts were created for. Knowing the anatomy of a breast, as well as the hormonal make-up as it relates to milk production, can be helpful if concerns about milk supply arise. While breasts come in all shapes and sizes, the internal anatomy needed to produce milk is generally universal. Listed below are a few components within the breast that contribute to the milk making process:

  • Glandular Tissue– This is tissue within the breast that contain alveoli and milk ducts
  • Alveoli– These are the cells where milk is actually produced
  • Ducts– These are the canals that transport milk towards the nipple of the breast
  • Adipose Tissue– This is fatty tissue intermittent with glandular tissue to protect the breast. (This fatty tissue is the main contributor in varying breast size among women, and in no way affects the ability of a woman to produce milk. Large breasts and small breasts can all produce milk!)
  • Progesterone- The pregnancy hormone that produces colostrum
  • Prolactin- The hormone that produces mature milk after delivery
  • Oxytocin- The hormone that triggers the release of the milk from the breast


During pregnancy, progesterone is the happy hormone that flows rampant in a woman’s body and is needed to sustain a healthy baby. Progesterone also settles in receptor sites within the breast, which signals the pituitary gland to produce colostrum. Colostrum is the extremely beneficial first milk your baby drinks for the first two days or so, and you will not produce very much of it. This is where some moms get concerned and fear their baby is going hungry. Not to worry! The baby’s stomach is only about the size of a marble at this point and can only hold the amount of colostrum that you are currently producing! After the complete delivery of the placenta, progesterone drops drastically, and with a lot of skin-to-skin and suckling, the brain is signaled to replace the progesterone receptor sites with prolactin. Prolactin increases as you nurse and this signals your body to create more milk. By day 3-5 you should be producing the mature milk and more of it than you were producing with colostrum, just around the same time that your baby’s belly has grown enough in size to hold more milk. This process was designed this way!

In my experience with Alice, our second night together she was much more insistent on staying at the breast and I nursed her literally nonstop for five hours and just kept switching sides. This exhaustive experience was telling my body that there was a big demand for the mature milk and this baby was ready for it! My body soon picked up on Alice’s demand and my milk came in with a vengeance once we were home.

Oxytocin is another important hormone in the breastfeeding process. Oxytocin is released when the breast is being stimulated by suckling and it triggers the alveoli cells to release the milk into the milk ducts that travel to the end of the nipple, otherwise known as a “let-down reflex”. Oxytocin is a “feel good” hormone and is often associated with the feeling of being in love, and may explain why mothers feel a strong bond with their breastfed baby.

This overview is only the beginning phase of producing milk and your body knows how to do it! The continuation of milk production is dependent on stimulation to the breasts and the frequent removal of milk. Be patient and keep your baby close. Do a lot of skin-to-skin and nurse as frequently as the baby is interested. This will signal your body to produce more milk, just as it was designed to do.