Breast Milk Production

The breasts are milk-producing glands in females primarily composed of connective and fatty acid tissues that cover and protect the milk-producing cells in female breasts. Alveoli are small, milk-producing cells activated by the secretion of prolactin hormone from pituitary glands in the brain. Milk from breast alveoli moves through milk ducts towards the breast nipple and secrete into the baby’s mouth. Breastmilk contains amino acids, electrolytes, fats, and other essential nutrients required for the nourishment and growth of newborn babies.

Highlights

• The breasts are milk-producing glands in females primarily composed of connective and fatty acid tissues.
• The breast alveoli are small, milk-producing cells activated by the secretion of prolactin hormone from pituitary glands in the brain.
• Milk from breast alveoli moves through milk ducts towards the breast nipple and secrete into the baby’s mouth.
• Breastmilk contains amino acids, electrolytes, fats, and other essential nutrients required for the nourishment and growth of newborn babies.

What are breasts and breastmilk?

The breasts are milk-producing glands in females. These glands are responsible for producing milk to nourish the newborn child with nutrients, fats, and proteins required for the baby’s growth. Breasts can vary in size, depending on the number of fats in breasts and family history. Pregnancy and breastfeeding practices also increase the size of your breasts. Similarly, milk production from breasts does not depend on breasts’ size; in fact, milk production from breasts follows a simple “demand and supply” rule. It means that the more you breastfeed, the more milk your breasts produce (Figure 1).

Types of breast milk

There are two types of breast milk which are colostrum and mature milk.

1. Colostrum is the first milk your breasts produce after you give childbirth. Colostrum is usually sticky, thick, and yellowish milk that contains almost three times more nutrients than mature milk. The colostrum does not contain fats and sugars. It has high levels of proteins, particularly β-carotene protein, that gives it a yellow appearance. Besides, colostrum also contains an excess of antibodies that make it thick. These antibodies are essential in providing natural immunity to newborns and cause a release of the first stool called meconium.
2. Mature milk is any milk after 48-72 hours of childbirth. It changes and increases in size with time, and it usually has two parts which are:
3. Foremilk: It is the first milk that your baby receives when you start breastfeeding. The foremilk is usually light blue and thin due to the excess of water to satisfy your baby’s thirst.
4. Hindmilk: It is the milk that comes from the breasts after several minutes of breastfeeding. The hindmilk is thick with a creamy appearance due to high fats. It has a relaxing effect, satisfies your baby’s needs, and helps them gain weight. Breastfeed your babies until they look sleepy and release sucking force on your nipples.

How is the milk production process completed?

The milk production process cannot complete until three “Bs” work together. These Bs include breasts, brain, and baby (Figure 2).

Role of Breasts

Breasts are the main part of the milk production process because they produce and secrete milk. In the second trimester (second three months: 4th, 5th, and 6th month) of fetus development, the pregnancy hormones cause the formation of milk ducts in female breasts. These ducts gradually divide into smaller ducts called ductules that further branch into grape-like clusters called alveoli. A single grape or alveoli is a lobule, while a bunch of alveoli is a lobe. There can be as many as 20 lobes in a breast, with a single milk duct in each lobe.

Discussing a lobule or alveoli, it takes nutrients, carbohydrates, proteins, and fats from blood to make breast milk. As the milk produces and accumulates in the breasts, it causes swelling of the breasts, and they get ready for breastfeeding. However, understanding when the breast glands produce milk primarily depends on the role of the brain and baby.

Role of brain

A female with mature milk ducts and alveoli in a breast cannot produce milk until the alveoli do not receive a milk-producing hormonal signal from the brain. It means that the brain plays an essential role in milk production. Without a brain signal, the first “B” (that represents breasts) of the milk production process is almost useless even with fully mature milk ducts. When the brain receives a suckling signal from the neural network of breasts, it sends a signal to pituitary glands to release prolactin hormone. The prolactin stimulates alveolar cells of the breasts to produce milk. In response, breast alveoli take nutrients and other essential compounds from blood and start making milk.

Once alveoli fills with the sufficient milk, breasts send a nerve signal to the brain to produce another hormone, “oxytocin” from the hypothalamus. Oxytocin stores in and releases from the pituitary glands and causes contraction and squeezing of the milk from alveoli into the milk ducts that travel towards the breast nipple.

Role of Baby

Now, we understand that the roles of the brain and breasts in a milk production process are interdependent, but they both depend on the baby. The role of a baby is critical in the milk production process because it is a baby’s sucking the breast nipple that sends a neural signal to the brain for secretion of prolactin hormone from pituitary glands. While it is already understood that prolactin stimulates alveoli for milk production, followed by contraction and squeezing of alveoli to secrete milk from breast nipples. The more your baby drinks breast milk, the more milk your body makes to fulfill milk demand. That’s why the milk production process follows a “demand and supply” rule.

Benefits of breastfeeding

• Breastmilk is the best source for feeding your baby as it contains almost all the nutrients required for growth.
• Breastmilk contains antibodies that give your children natural immunity to fight off infections.
• Breastmilk protects your children from multiple diseases and illnesses such as type 1 diabetes, obesity, asthma, SIDS (sudden infant death syndrome), ear infections, stomach bugs, etc.

Breastfeeding decreases the chances of type 2 diabetes, high blood pressure, and ovarian and breast cancer in mothers.