Engorgement is a swelling of the breasts caused by expanding veins and the pressure of new milk. Many, but not all women experience engorgement usually two to six days after delivery. Immediately after birth, the mother produces colostrum, a yellow, sticky fluid secreted by the breasts that provides nutrition and protection against infections.
Colostrum contains more protein, less sugar and much less fat than mature breast milk.
However, engorgement can also happen later if lactating women miss several nursings and not enough milk is expressed from the breasts. The degree of engorgement usually lessens with each child. When the breasts switch from colostrum to mature milk, some feeling of fullness, swelling, and discomfort are normal. However, when breasts become engorged, they are more prone to infections, and therefore, preventative measures should be taken to avoid and reduce engorgement. Some suggest not going more than three hours without nursing and not skipping night feedings.