How is breast milk made? How the body produces breast milk

During pregnancy:

During pregnancy, the placenta releases the hormones lactogen and progesterone, and the anterior pituitary gland releases prolactin, which stimulates the glandular tissue to grow and prepares the milk sacs (alveoli) to produce milk.
In general, during pregnancy the breasts become softer and larger, and the colour of the nipples and areolas changes. The small bumps on the areola, called Montgomery glands, become larger and more visible. They release an oil that lubricates the nipple, preventing dryness, cracking and infection when you breastfeed.
After birth:

• After your baby is born, the placenta is also delivered, so progesterone levels fall, allowing the hormone prolactin to start working. Prolactin then "signals" to the breasts that it is time to produce more milk:
• At first, colostrum is produced. It is pale yellow, rich in immune cells and antibodies, and low in fat. Colostrum has a laxative effect, helping your baby pass meconium more quickly and reducing jaundice after birth.
• From day 3-7, breast milk gradually increases in quantity and its composition changes: protein gradually decreases while lactose and fat gradually increase to meet your baby's needs. This is called transitional milk.
• From day 7 onwards, the nutrients in breast milk become more stable. The amount of milk will depend on your baby's needs, that is, how many times a day your baby feeds.

How milk is released:

Two hormones are mainly responsible for producing milk and moving it out of the breast: prolactin and oxytocin.
Milk production is triggered by the hormone prolactin, which is released in your body when your baby breastfeeds. So the more your baby feeds, the more milk you produce.
When your baby feeds, their mouth and tongue touch the nipple and areola, and sensory impulses travel from the nipple to the brain, stimulating the pituitary gland to release the hormone oxytocin. Oxytocin makes muscle cells contract, squeezing the milk sacs and milk ducts to push milk into the milk sinuses (under the dark area of the areola) and out through the tiny openings in the nipple. This is when milk is transferred out of the breast (also called the let-down reflex)

• Factors that help or block the let-down reflex:

The let-down reflex is also called the oxytocin reflex. So anything that affects a mum's state of mind has a big effect on stimulating the pituitary gland to release oxytocin.

1. Factors that help the let-down reflex:
- Not feeling pain
- Skin-to-skin contact with your baby
- Watching, listening to, smelling and cuddling your baby
- Your baby feeding effectively
- Feeling confident
- Feeling relaxed
- Getting enough rest
2. Factors that block the let-down reflex:
- Pain
- Being separated from your baby
- Your baby not feeding effectively
- Lack of confidence
- Negative emotions and worry
- Feeling tired
If you have any factors that block the let-down reflex, try to rest and relax, and contact a health worker or specialist for support.
You can use the following methods to stimulate the let-down reflex before breastfeeding directly or expressing milk:

1. Drink 1 cup of warm milk or 1 glass of warm water about 10 minutes before feeding/expressing
2. Skin-to-skin contact with your baby
3. Apply a warm compress to both breasts (for at least 3 minutes)
4. Breast massage and back massage.

References:

https://www.youtube.com/watch?v=extZN-NYlIc&t=294s

The let-down reflex