The appearance and function of the breasts are controlled by changes in hormones.
The breasts are constantly changing from puberty, adolescence, the childbearing years and into the menopause. Changes are a normal part of getting older.
Breasts begin to form during fetal development, with a thickening in the chest area called the mammary ridge or milk line. By the time a female infant is born, a nipple and the beginnings of the milk-duct system have formed.
One of the first signs of puberty is when the breasts start developing. Many girls start to get “breast buds” (mounds or bumps around or under the nipple) at an average age of 11, although it can start at a younger or older age.
Shortly after the development of “breast buds” the entire breast will start to get larger. The nipple and areola (the area around the nipple) will get darker and form a separate, small mound. This whole process, from “flat” to “finish” takes from 2 to 3 years. Some girls develop more quickly than others and the majority of adult women have one breast that’s bigger than the other.
Once the breasts have developed, changes linked to the monthly menstrual cycle are common.
Just before a period, breasts may become larger, tender or feel a bit lumpy. After a period, this lumpiness becomes less obvious or may disappear altogether although some women may have tender, lumpy breasts all the time.
During pregnancy, the breasts get much larger as the number of milk-producing cells increases.
Around the menopause lumps and tenderness are common. The lumps often turn out to be breast cysts (benign fluid-filled sacs, which are not dangerous).
Breast tissue also changes with age and begins to lose its firmness when the milk-producing tissue is replaced by fat, making the breasts sag. This is more noticeable after the menopause, when oestrogen levels fall.
As you grow older, your breasts may change size too. If you take HRT (hormone replacement therapy) your breasts may feel firmer and sometimes quite tender. The breasts naturally head southwards through aging, as the ligaments become elongated.
Like any body part, breasts change as you get older, but it is perfectly normal and all part of being human.