1st Trimester Breasts
During pregnancy, a number of changes occur over time which prepare
the breast for lactation.
- Early in the first trimester, the breasts and nipples become
tender. The tenderness persists until the end of the 1st trimester, at
which time the tenderness disappears.
- By the end of the first trimester, enlargement of the breast and
nipple is noticeable.
- By the third trimester, the breast and nipple have experienced
further enlargement and the Montgomery's glands around the periphery
of the areola become more pronounced.
- The nipples gradually darken, becoming dark brown or black by full
While these visible changes are occurring, endocrinologic changes are
preparing the breasts for lactation, requiring estrogen, progesterone,
insulin, cortisol, prolactin and human placental lactogen. Ultimately,
the breasts are prepared for the alveoli to secrete milk.