The size and shape of women’s breasts varies considerably. Some women have a large amount of breast tissue, and therefore, have large breasts. Other women have a smaller amount of tissue with little breast fat.
Factors that may influence a woman’s breast size include:
- Volume of breast tissue
- Family history
- Age
- Weight loss or gain
- History of pregnancies and lactation
- Thickness and elasticity of the breast skin
- Degree of hormonal influences on the breast (particularly estrogen and progesterone)
- Menopause
A woman’s breasts are rarely balanced (symmetrical). Usually, one breast is slightly larger or smaller, higher or lower, or shaped differently than the other. The size and characteristics of the nipple also vary greater from one woman to another. In some women, the nipples are constantly erect. In others, they will only become erect when stimulated by cold or touch. Some women also have inverted (turned in) nipples. Inverted nipples are not a cause for concern unless the condition is a new change. Since there are hair follicles around the nipple, hair on the breast is not uncommon.
The nipple can be flat, round, or cylindrical in shape. The color of the nipple is determined by the thinness and pigmentation of its skin. The nipple and areola (pigmented region surrounding the nipple) contain specialized muscle fibers that respond to stimulation to make the nipple erect. The areola also houses the Montgomery’s gland that may appear as tiny, raised bumps on the surface of the areola. The Montgomery’s gland helps lubricate the areola. When the nipple is stimulated, the muscle fibers will contract, the areola will pucker, and the nipples become hard.
Breast shape and appearance undergo a number of changes as a woman ages. In young women, the breast skin stretches and expands as the breasts grow, creating a rounded appearance. Young women tend to have denser breasts (more glandular tissue) than older women.
During each menstrual cycle, breast tissue tends to swell from changes in the body’s levels of estrogen and progesterone. The milk glands and ducts enlarge, and in turn, the breasts retain water. During menstruation, breasts may temporarily feel swollen, painful, tender, or lumpy.
THE EFFECTS OF HORMONES ON BREAST TISSUE
The breast is responsive to a complex interplay of hormones that cause the breast tissue to develop, enlarge and produce milk. The three major hormones affecting the breast are estrogen, progesterone and prolactin, which cause glandular tissue in both the breast and uterus to change during a woman's menstrual cycle. Because of reduced hormonal levels, the breasts are less full for 1 to 2 weeks after menstrual flow; therefore, it may be easier to detect breast lumps during this time. Reduction of hormonal levels is also responsible for the breast's return to its pre-pregnant state after breast-feeding is concluded.
Breast shape and appearance change as a woman ages. In the young woman the breast skin is stretched and expanded by the developing breasts. The breast in the adolescent is usually hemispherical, rounded and equally full in all areas. As a woman gets older, the topside of the breast tissue settles to a lower position, the skin stretches and the shape of the breast changes. After menopause, with the decrease of hormonal activity, the composition of the breast changes; the amount of glandular tissue decreases and fat and ductal tissue become the predominant components of the breast. Reduction in glandular volume can result in further looseness of the breast skin
