The breasts are composed of fat, which determines breast size and shape; glands, which produce milk; and connective tissue that provides support to the breasts, according to Columbia Health Services. A number of factors can affect each of these breast tissue components, resulting in breasts taking on a sagging appearance. This may result in nipples that point downward or tissue that appears loosened. While other factors related to pregnancy may cause sagging breasts, it is important to note that breastfeeding does not, according to the American Society of Plastic Surgeons.
When a person smokes, the carcinogens contained in the smoke enter the body and cause elastin to break down in the body, according to the Mayo Clinic. Elastin fibers are responsible for skin elasticity, meaning the absence of the fibers causes the skin to droop. These fibers are found in breast tissue and, over time, smoking can lead to tissue breakdown that results in sagging breasts, according to the American Society of Plastic Surgeons.
Yo-Yo Dieting and Pregnancy Weight Gain
According to Dr. Diane L. Gibby with The Women's Center for Plastic and Cosmetic Surgery, yo-yo dieting causes the breast to lose fat tissue, which can cause the breasts to appear less firm. If you gain the weight back, your body's ligaments may not be in place to support the tissue, resulting in sagging breasts. The same principle is true for women who become pregnant and gain weight in the breasts due to carrying a baby, then lose the weight once the baby is born.
As you age, your body's elastin fibers, which keep the skin from drooping, and collagen fibers, which give tissue strength and flexibility, decrease. The rate at which they decrease is determined chiefly by genetics, according to Columbia Health Services. Women may notice this effect especially during menopause, when collagen fibers decrease at their fastest rate.
Gravity's pull affects larger breasts more than smaller breasts, which can cause them to take on a naturally sagging appearance. For this reason, it is important to wear a bra that provides sufficient support to combat gravity's effects.
High-impact exercises, such as running and jogging, can stretch ligaments in the breast, says Sabrena Merrill, spokeswoman for the American Council on Exercise, on Shape.com. These activities place more stress on the breast tissue if the breasts are not properly supported through the wearing of a jogging bra or other clothing item that adds extra support and keeps breasts from moving.