How is breast milk produced?

The production of breast milk can be altered due to physical or psychological reasons. As such, it’s crucial to seek help from a medical professional to resolve any issues.
How is breast milk produced?

Last update: 27 May, 2022

Pregnant women tend to quickly notice changes in their breasts appearance and sensitivity. Yet, many are unaware of the physiological process of producing breast milk. There let’s get you acquainted with the female breast anatomy and the transformation that enables milk production.

Female breast anatomy

Mother and baby

You must first know about the female breast structure and functions, in order to understand how breast milk is produced. Female breasts are complex; they’re made up primarily of fatty and connective tissue. Their main function is to protect and support its milk-producing parts.

Milk production involves many small groups of cells called alveoli. Once produced, the liquid travels to the nipple, passing through the milk ducts. The lactiferous ducts are located behind the areola which surrounds the nipple and temporarily stores breast milk.

How is breast milk produced?

Suction stimulates the nerve endings loctaed on the nipple and areola. It sends a signal to the brain in order to trigger the production of two hormones called prolactin and oxytocin.

  • Prolactin causes the alveoli to absorb protein, sugar, and other nutrients from the bloodstream. This combination will form the nutritional basis for producing breast milk.
  • Oxytocin enables the alveoli to compress and expel milk from the nipples.

When a baby nurses, its tongue and jaw movements put pressure on the nipple. As a result, the milk flows from the breast to the nipple, which has up to 20 tiny holes where the milk passes through.

Changes in a woman’s breasts during pregnancy

Pregnant woman

During pregnancy, a woman will visibly notice her breasts becoming larger. Furthermore, the areolas and nipples swell and darken considerably. All of this helps the baby’s suction and improves their “latching ability”, providing the baby peace and comfort.

Additionally, the areola also has small bumps called montgomery glands that can be felt during pregnancy. The glands make a natural oil, whose function is to constantly clean, lubricate, and protect nipples while a woman breastfeeds. It prevents cracking, wounds, and other injuries due to dehydration and strong suction.

Finally, remember to clean the breasts. You should water or other products made for nursing women. Conventional soaps and cosmetics can change the breasts’ texture. They can also remove the protective oil and irritate the baby’s mouth and mucosa membrane.

Changes from breast milk production: causes and symptoms

Many women are affected by changes from breast milk production while being pregnant or during nursing. Symptoms can be minor, such as breastfeeding pains, and changes in milk letdown or flavor.

  • There’s no reason for a healthy baby to reject breast milk. Therefore, it’s important to contact a physician in case there are any changes in the baby’s behavior.
  • In some cases, a woman can stop producing breast milk withing the first days after giving birth.
  • There are also certain metabolic disorders that can inhibit the proper milk ducts development.

These possibilities reaffirm the need for medical guidance throughout a pregnancy and while nursing.

Causes of breastfeeding problems

Baby nursing
  • Fatigue, exhaustion, or elevated stress
  • Negative mood, depression, or constant irritation
  • Mood swings: fear, shame, anger, resentment, irritation, etc.
  • Improper techniques or positions while nursing (which make sucking harder for baby)
  • Inadequate breastfeeding (insufficient timing, long periods without nursing, etc.)
  • Unfavorable environments: household conflicts, stressful locations, hectic schedules, etc.
  • Fears or misconceptions about breastfeeding, such as the fear of pain while nursing or rejection by a partner
  • Breast engorgement (common in the first days of nursing)

As you can see, most changes in breastfeeding stem from emotional or psychological issues. It’s important that the baby and nursing mother live in favorable conditions for their physical and emotional development.

Thus, it’s necessary for the family to work towards a healthy pregnancy and a positive nursing experience.

Talk to a medical professional for further information on producing breast milk and recommendations for a healthy breastfeeding experience.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.


  • Stanford Children’s Health. Anatomía de las mamas.
  • stanfordchildrens.org/es/topic/default?id=anatomadelossenos-85-P03255

  • Sutter Health. Cómo se Produce la Leche Materna.
  • bebes.sutterhealth.org/breastfeeding/bf_production.html

  • M. Blázquez. Curso de Medicina Naturista. (2003). Anatomía y Fisiología. Anatomía de la mama durante la lactancia.
  • unizar.es/med_naturista/lactancia%203/-Anatomia%20y%20Fisiologia.pdf

  • J. Martinez, V. Valdés. Problemas en la Lactancia.
  • .unicef.cl/lactancia/docs/mod03/Mod%203%20Problemas%20de%20lactancia%2018%20feb%2005.pdf


This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.