After the many changes a woman’s body goes through during pregnancy, she may be surprised to see that the physiologic changes do not stop once the baby is delivered. A woman’s breasts begin the process of lactation during pregnancy, and this process comes to maturity in the days following delivery. Breast growth after pregnancy is largely due to lactation, or milk production for the mother’s new baby.
Preparatory Breast Changes in Pregnancy
One of the first symptoms of pregnancy is swelling and tenderness in the breasts. Pregnancy hormones stimulate mammary tissue so that it can begin laying down the foundations for milk production after birth. This is the beginning of growth and size changes that will continue after birth. For many women, the appearance of colostrum, or early pre-milk, in the second or third trimester indicates that their body is ready to nourish their new baby. Colostrum is a thick, slippery fluid that is high in protein. It provides complete and total nutrition for a newborn baby.
Birth to Day Three
As the baby and placenta are delivered, new hormones signal the mother’s brain and breasts to begin the production of mature milk. The breasts continue to produce colostrum, but now the process slowly changes to that of mature milk production. Breast tissue may increase in size over the course of these few days, but the change will not be drastic until mature milk production begins.
Days Four to Six
For most women, colostrum begins to change to whitish milk sometime during these first few days. When this happens, the breasts will generally increase in size and may even become engorged. When a breast is engorged, the milk production has out-paced milk expression and the breasts feel large, swollen, hot and sometimes painful. According to lactation consultant Linda Worzer of Natural Beginnings in Dallas, Texas, allowing a baby to nurse or expressing the milk with a breast pump will empty the breasts and relieve the engorgement. Mothers should feel relief immediately after pumping or nursing.
However, if a mother does not wish to or cannot feed her baby breast milk, pumping is not recommended because it will only serve to signal her body to create more milk, causing worsening engorgement to re-occur a few hours later. Instead, she should use massage, cool compresses and a pain reliever such as ibuprofen. Engorgement should last only five to seven days.
Three to Six Weeks Post Partum
After the rapid breast growth of the first week post partum, a mother’s milk supply continues to regulate to meet her baby’s demand. Some of the breast growth that occurred due to over-supply will diminish, but there will generally be an increase in size from the mother’s pre-pregnancy measurements (assuming that she continues to nurse her baby). This increase is due to greater fluid content in the breasts, increased mass of mammary glands and fat from pregnancy weight gain.
Six Weeks and On
By six weeks post partum, a mother’s milk supply should be well established and breast size will have nearly settled into its final measurement for the duration of nursing. There might still be fluctuations in size due to periodic engorgement from a missed or poor feeding, but these times will be rare if the mother-baby duo are feeding on demand. If a mother is not back at her pre-pregnancy weight at this time, there may also be continued loss of breast size as fat is lost in the breast tissue.
References
- Linda Worzer, IBCLC; Natural Beginnings Childbirth and Breastfeeding; Dallas, Texas
- La Leche League International: My breasts feel extremely full and uncomfortable
- La Leche League International: What is colostrum? How does it benefit my baby?
