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Volume of breast tissue
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Family history
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Age
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Weight loss or gain
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History of pregnancies and lactation
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Thickness and elasticity of the breast skin
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Degree of hormonal influences on the breast (particularly estrogen and progesterone)
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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.
