One of the first questions that we will address is when milk comes in after delivering a baby. When you give birth, your body goes through many hormonal changes. The hormone prolactin triggers the production of breast milk. The level of prolactin needs to increase to produce breast milk.
The first fluid that is expressed from your breasts after birth is called colostrum, which is the most potent natural immune booster known to science. This sticky, yellow substance begins production during late pregnancy and contains nutrients for your baby's first few days of life.
It also contains antibodies to protect your baby against infection and acts as a natural laxative for your baby's first bowel movements (containing meconium). Newborns usually drink colostrum for 2–3 days before breast milk production starts.
The next stage of breast milk production is called the transitional milk flow. This form of breast milk lasts for the first few weeks after the production of colostrum has stopped. This milk contains higher levels of lactose, fat, and water-soluble vitamins.
After this, mature breast milk production begins. This milk contains approximately 90 percent water and 10 percent proteins, fats and carbohydrates. This milk keeps your baby well hydrated and is easily digestible.