Breast milk has three different and distinct stages: colostrum, transitional milk, and mature milk. Colostrum Colostrum is the first stage of breast milk. It occurs during pregnancy and lasts for several days after the birth of the baby. It is either yellowish or creamy in color. It is also much thicker than the milk that is produced later in breastfeeding. Colostrum is high in protein, fat-soluble vitamins, minerals, and immunoglobulins. Immunoglobulins are antibodies that pass from the mother to the baby and provide passive immunity for the baby. Passive immunity protects the baby from a wide variety of bacterial and viral illnesses. Two to four days after birth, colostrum will be replaced by transitional milk. Transitional milk Transitional milk occurs after colostrum and lasts for approximately two weeks. The content of transitional milk includes high levels of fat, lactose, and water-soluble vitamins. It contains more calories than colostrum. Mature milk Mature milk is the final milk that is produced. 90% of it is water, which is necessary to keep the infant hydrated. The other 10% is comprised of carbohydrates, proteins, and fats which are necessary for both growth and energy. There are two types of mature milk: Fore-milk: This type of milk is found during the beginning of the feeding and contains water, vitamins, and protein. Hind-milk: This type of milk occurs after the initial release of milk. It contains higher levels of fat and is necessary for weight gain. Both fore-milk and hind-milk are necessary when breastfeeding to ensure the baby is receiving adequate nutrition to grow and develop properly. You might also be interested in taking a comprehensive breastfeeding supplement to help deliver vitamins, minerals, and nutrients that are important for healthy and plentiful breast milk production.