when does colostrum come in

Colostrum, the first form of breast milk, begins to be produced and can appear as early as around 16 weeks into pregnancy. After birth, colostrum is the initial milk your breasts produce and it typically lasts for the first few days, about 2 to 4 days after birth. Around three to five days postpartum, colostrum transitions to transitional milk as the mature milk supply increases. The colostrum is nutrient-rich and highly beneficial for newborns, providing essential antibodies and nutrients needed in the first days of life. Breast milk usually comes in with a feeling of firmer breasts after this colostrum phase, generally within several days after delivery.