Newborns Breastfeeding Breast Changes

Early in my pregnancy a friend of mine brought over some of her old nursing bras. “You’ll need these,” she said. I accepted them graciously even though I knew my body would never fill the melon-sized garment. But pregnancy does interesting things to the body and my former flat look was transformed into a curvaceous 38D! My new body type was flattering, albeit uncomfortable.

While not every woman is transformed to the same degree, her body changes significantly as it readies itself for the feeding of her baby. Some women have a tremendous increase in breast size and most women experience firmness and tenderness in the breast. These changes are a result of the body’s natural ability to create breast milk during lactation.

Breast AnatomyColostrum and Breast Milk Production

Just after the baby is born the breasts produce an immune-rich substance called colostrum. Colostrum is full of protein and keeps the baby full with small, frequent feedings until the breast milk comes in.

The mother’s body goes through a fluid shift two to five days after birth. The body is preparing itself for breastfeeding as the breast tissues swell with blood, lymphatic fluid and milk. This process makes the woman’s breasts fuller and more tender and it may also cause a low fever. Some women complain of overall discomfort.

Breast Engorgement and Breast Pumps

Breast milk may come in rapidly. Regular and frequent feedings keep the milk flowing freely and help prevent engorgement. Engorgement is the swelling of the breasts when they’re full of milk.

A slight engorgement is normal and may cause swelling or tenderness. Sometimes, women have to pump out extra milk and store it in the freezer to prevent the breast from becoming too engorged. A breast pump can help to release excess milk and prevent further engorgement. Severe breast engorgement can lead to more serious breast infections like plugged milk ducts or mastitis.

The Milk Let Down Reflex

Once a feeding routine has been established, the body keeps its own internal clock. Within two to four weeks, the body’s let down reflex is established. The milk let down reflex is triggered when the baby suckles at the breast. The nerves send a signal to the brain to release oxytocin, the hormone that signals the milk ducts to squeeze out milk.

Milk let down occurs naturally but can vary among women. Some women don’t feel the let down at all while some women feel a tingling sensation. Some women let down with the sound of their baby’s cry. Other women might need to relax or drink fluid to encourage let down. Using a breast pump to express some milk may also help to activate the milk let down reflex.

As natural as breastfeeding is, some women need time before it feels comfortable. Positioning and technique can give positive results. Finding the best routine for yourself can result in a beautiful bonding time for you and your baby.


American Academy of Family Physicians. (updated 2003). Breast feeding: Hints to help you get off to a good start.

American Academy of Pediatrics. (updated 2004). A woman’s guide to breastfeeding.