The key parts of the female breast include:. At the onset of puberty, female reproductive hormones — particularly estrogen —guide breast growth. Normal changes in the breast during pregnancy can include firming, enlarged nipples, darker nipples, and stretch marks on the skin due to enlargement. Another difference between the breasts of men and women are the amount of nerve endings in the nipples and surrounding tissues.
Breast Buds: Everything You Need To Know | Becoming a Teen
It starts with a firm, round, tender lump called a breast bud under the nipple of one or both breasts. Girls may complain about feeling sore when they sleep on their stomachs; parents occasionally worry about the lump being a cyst or tumor. One side may develop considerably faster than the other. This is normal.
Jump to navigation. Breast development is caused by hormones released by the ovaries at puberty. These hormones cause fat to accumulate, causing your breasts to enlarge.