Your breasts produce colostrum beginning during pregnancy and continuing through the early days of breastfeeding. This special milk is yellow to orange in color and thick and sticky. It is low in fat, and high in carbohydrates, protein, and antibodies to help keep your baby healthy. Colostrum is extremely easy to digest, and is therefore the perfect first food for your baby. It is low in volume (measurable in teaspoons rather than ounces), but high in concentrated nutrition for the newborn. Colostrum has a laxative effect on the baby, helping him pass his early stools, which aids in the excretion of excess bilirubin and helps prevent jaundice.
The colostrum gradually changes to mature milk during the first two weeks after birth. During this transition, the concentrations of the antibodies in your milk decrease, but your milk volume greatly increases. The disease-fighting properties of human milk do not disappear with the colostrum. In fact, as long as your baby receives your milk, he will receive immunological protection against many different viruses and bacteria.