Why Do Girls' Breasts Get Bigger?

There are many factors that influence growth of breasts. These include nutrition and genetics, both because of hormone stimulation. Breast growth is one of the important things that happens during puberty. The pubertal hormones produced by the pituitary gland (located in the brain and responsible for producing a variety of hormones), play a critical role. One of the earliest signs that puberty has begun is enlargement of the breasts as a result of increased production of ovarian estrogen stimulated by these pituitary hormones. Boys also often experience breast enlargement during the early stages of their pubertal growth spurt, but their breasts usually shrink in size after one or two years. As long as estrogen continues to be secreted in females, breasts will grow and/or maintain their size. Breasts may also enlarge slightly in women taking birth control pills or, after menopause, estrogen-replacement pills. Naturally, breasts enlarge during pregnancy as a result of marked increase in estrogen secretion. Girls with poor diets and weight loss may notice that their breasts get smaller. If these girls improved their nutrition, their breasts would enlarge to their previous size