Breast milk has three different and separate stages: colostrum, transitional milk and mature milk.
Colostrum: Your breasts start getting ready for breastfeeding halfway through your pregnancy by making colostrum. This milk is thick, is either yellowish or creamy in color, and in the perfect first food for your newborn baby. Colostrum is high in protein, fat-soluble vitamins, minerals, and antibodies that protect your new baby from infections.
Transitional Milk: Two to four days after birth, colostrum will be replaced by transitional milk, which lasts about two weeks. Transitional milk contains high levels of fat, lactose, and vitamins. I contains more calories than colostrum to help your baby continue to grow and get stronger.
Mature Milk: Mature milk is the final milk that is produced. 90% of mature milk is made up of water, while the other 10% is carbohydrates, proteins, and fats that are important for growth and energy. Your mature milk will change its makeup to meet the needs of your baby. It is unique and specially made by your body just for your baby.
During the first couple of weeks, your breast milk will change with the growth of your baby.