Breast development points to the process from development to maturity after birth as the hypothalamus-pituitary-ovary function is perfected, which can usually be divided into five stages. Although there is a certain pattern of breast development, there may be some individual differences in development due to genetic, environmental and nutritional influences: 1. Neonatal period: Due to the influence of the placenta and the estrogen produced by the mother in the mother’s body, some newly born girls have a slight augmentation or a small amount of lactation in the breast area; 2. Childhood period: Before the age of 8, because the organism does not secrete a large amount of sex hormones, the At the age of 8 to 12, the body begins to release sex hormones, thus beginning to appear breast development, fat in the chest subcutaneous tissue began to accumulate, girls began to appear female characteristics; 3, puberty: generally refers to 10-17-year-old women, at this time, the secondary sexual characteristics of women began to gradually develop to maturity, female breasts gradually full, the glands at the breast development mature, this time girls often 4, sexual maturity: generally refers to the age of 18 years after about 30 years, the most vigorous female endocrine function of the period, women’s breasts have been developed and mature, in the sex hormone catalysis of cyclical changes; 5, pregnancy: some women in pregnancy or lactation due to changes in the level of sex hormones, milk filling and other circumstances, the second breast development may occur. In addition, as the body ages, the breast state will change. After menopause, women’s sex hormone levels gradually decline, which is not enough to maintain female secondary sexual characteristics, resulting in the atrophy of the breast glands, the reduction of fat, resulting in breast sagging elasticity reduction and other conditions.