Breast enlargement is simply a structural disorder of the mammary glands caused by a woman’s endocrine disorders, that is, an increase in estrogen and a decrease in progesterone. Endocrine disorders are the main reason for the development of breast enlargement. The causes of breast enlargement are as follows: First, the symptoms of the breast are synchronized with the changes in the breast tissue. That is, it changes with the menstrual cycle, that is, with the cycle of estrogen and progesterone in the body, the hyperplasia and regrowth occur week after week. The main histological lesion of breast hyperplasia is the excessive proliferation and incomplete recovery of the breast essence, this phenomenon is due to the imbalance of the ratio of estrogen and progesterone. Second, breast hyperplasia from the age of onset, most patients are sex hormone secretion period, the disease is rare in puberty, decline after menopause, consistent with the rise and fall of ovarian function. Third, from the irregularity of breast lesions on the breast, also indicates that it is caused by endocrine influence. From the clinical point of view, most of the patients with breast hyperplasia, occurred in the side of the non-lactating, or non-lactating side of the symptoms are heavy. In the case of unmarried and childless patients with breast hyperplasia, the disease can be relieved or cured after pregnancy, childbirth and breastfeeding.