At about four weeks of age, and at least two weeks before you return to work, begin introducing a bottle of pumped milk. You can pump before a feeding and let someone else feed the baby, since many breastfed babies will not easily take a bottle from their mother. After one month of age, the volume of milk a baby drinks at a feeding doesn’t change much. A healthy baby born at term will usually drink between 3 and 4 ounces at a feeding, and rarely more than 5 ounces. Be sure to inform your baby’s caregiver about how often and how much your baby usually eats. Ask that your baby is fed whenever he says he is hungry and be allowed to stop when he says he has had enough. Many mothers find that storing breastmilk in small quantities of one and two ounces helps to prevent wasting milk as the caregiver can add small quantities to a feeding as needed.
Storage guidelines for pumped milk are widely available online. You will find slight variations in recommendations from different sources. The CDC website has good recommendations. Fresh breastmilk is quite stable since it is filled with living cells. However, the digestive enzymes present in breastmilk can cause a change in the flavor. Refrigerating milk after no more than four hours at room temperature can help to prevent this change. Milk that is frozen no more than 48 hours after pumping will retain more of the immune factors that protect babies from colds and other respiratory illnesses. Once thawed, frozen milk must be used within 24 hours.
Many mothers feel more secure with a few ounces of frozen milk on hand “just in case”. Frozen milk can also be mixed with first foods when your baby starts solids at about six months of age, and given to a sick toddler for the immune protection. Breastmilk will keep for six months to a year in the freezer.