What is expressed breast milk? Expressed breast milk (EBM) is the process of squeezing milk from the breasts. This can be achieved through the use of your hand or the use of an electrical breast pump. Mothers who choose to pump should try to pump every two to four hours to completely empty their breasts in order to continue to produce enough milk to feed their infant. One of the main reasons why mothers decide to pump is to ensure that their infant will receive breastmilk when the mother returns to work or when the mother will be away from her infant for a long period of time. Another reason mothers may decide to pump is due to breast engorgement. Engorgement is a problem many mothers encounter when breastfeeding. Expressing breast milk helps to relieve engorged breasts. Electrical breast pumps are available to rent or buy. Contact your local lactation consultant for more information. How long is EBM good for? EBM can be kept: at room temperature for up to 10 hours when it has been freshly expressed from the breast. in the refrigerator for up to 8 days. in the refrigerator freezer for 8 days or in a deep freezer for 6 to 12 months. Once thawed, frozen EBM should be kept in a refrigerator for up to 24 hours.