I believe that the majority of women are deeply troubled by breast enlargement, very confused about how to prevent and treat it, next I tell you how breast enlargement is. Before talking about breast enlargement, we first recognize the mammary gland, how the mammary gland develops, and what changes it has undergone in its lifetime. First, embryonic human mammary glands from the ectoderm, in the sixth week of the embryo, the ectoderm appeared milk line (mammary gland line), the original epidermis was localized proliferation, the formation of the “mammary gland initiation base”; 9 weeks, the mammary gland initiation base gradually fade, the formation of nipple buds. At 9 weeks, the nipple bud gradually recedes and forms a nipple pit. The epithelial cells on the surface of the nipple bud gradually differentiate and proliferate to form a nipple pit; at 12 weeks, the nipple bud progressively evolves into a permanent milk duct. The nipple buds continue to grow downward, forming milk ducts that open into the cavities of the nipple recesses; at 36 weeks, solid epithelial cords with lumens form, and the milk ducts terminate in small clusters of basal cells, the precursors of the later lobules of the mammary glands. The connective tissue under the nipple continues to proliferate, and the nipple gradually protrudes outward. Second, the newborn period by the mother’s hormone level, about 60% of the newborn period mammary gland can have some degree of physiological activity, generally in the 3rd?4 days after birth can appear nipple secretion or nipple under the emergence of a 1?3cm hard knot, 1?3 weeks after the gradual disappearance of the mammary gland, known as physiological mastoid hyperplasia. Microscopically, the mammary glands were seen to contain moderately branched ducts with markedly dilated lumens containing pink secretions. The epithelial cells of the ducts in the terminal part are columnar, and there is loose connective tissue around the ducts, which is rich in blood-filled capillaries. Third, early childhood mammary glands are quiescent, manifested as degenerative changes in the mammary glands, only women’s quiescent state is incomplete compared to men, women can occasionally see the remnants of epithelial hyperplasia of the milk ducts change. At this time, the epithelium of the milk ducts gradually atrophies, presenting neatly arranged single layer of columnar and cubic cells, the lumen is narrowed or completely occluded, and the connective tissue around the milk ducts is vitreous. Fourth, puberty China’s female breasts begin to develop at the age of 12?15 years. The development of mammary glands advances accordingly with the improvement of material living standards. Generally, 1/3 of the people do not have menstruation in the fashion of mammary gland development. 1, the female mammary glands in the role of sex hormones, growth accelerated, mammary glands, areola, nipple successively enlarged. Disk-shaped hard nodules can be touched under the nipple. The coloring of the areola and nipple also increases gradually, and later the mammary gland gradually develops into a uniform conical shape. The main histologic basis for the enlargement of the mammary glands is interstitial fibrous hyperplasia and significant accumulation of subcutaneous fat. The morphologic changes in the mammary tissue do not differ much from those in early childhood (the milk ducts are moderately dilated, with a slightly widened lumen, columnar epithelium, and a small amount of secretion in the larger ducts. The periductal connective tissue is increased and lax, with abundant blood vessels). At this time there is no terminal duct and lobule formation. At the time of menstruation, the basal cells at the end of the small ducts proliferate and form the lobules, and then the lumen is gradually formed, finally forming the lobular structure of the mammary gland. 2, male mammary glands: male mammary glands develop to a lower degree, later than female, and the development period is also shorter. 60%?70% of men in this period can be touched under the nipple hard knot, mild tenderness. Generally, it will gradually subside after 1 or 2 years. E. Sexual maturity (an important stage in the emergence of breast hyperplasia) After puberty mammary gland development, the histological structure of the mammary gland has been nearly perfect, when the ovaries are mature, the level of sex hormones is cyclical changes, menstruation, the shape and histological structure of the mammary gland also have cyclical changes. Before the onset of menstruation, the level of ovarian endocrine hormones reaches its peak. Hormone action on the mammary glands shows proliferative changes; after menstruation, the level of endocrine hormones decreases, and the mammary glands show degenerative changes. 1, proliferative period: equivalent to the pre-menstrual period, starting from 5-7 days after the end of menstruation to the next menstrual period. At this time, the level of sex hormone gradually rises, and the epithelial cells of the milk ducts proliferate and become bigger. The lumen expands and new follicles are formed. At the end of hyperplasia, secretions can be seen in the milk ducts and lobules, and the epithelial cells of the ducts are hypertrophied, some of which are vacuolated. The periductal connective tissue is edematous and pale, and lymphocytic infiltration is seen, and this process reaches its peak before the onset of menstruation. Clinical manifestations of the breast volume increased, touching the nodular feeling, sometimes accompanied by mild swelling or tenderness. 2.Recovery period: the level of sex hormone decreases, menstruation occurs, and the mammary glands show degenerative changes. Lobular epithelial secretion is reduced, cell atrophy, shedding, lumen narrowing or occlusion, peritubular connective tissue tightened glassy change. Lymphocyte infiltration is reduced, and a few wandering phagocytes can be seen. At this time, the volume of the breast becomes smaller and softer, and the swelling or tenderness is reduced or disappears. A few days later, the sex hormone level changes with ovulation and the mammary gland re-enters the proliferative phase. During this period, with the cyclic changes in ovarian function, the mammary glands show corresponding cyclic changes, and the mammary glands are not fully developed until the period of pregnancy and lactation. At this time, if the mammary gland is over stimulated by estrogen, it will cause mammary hypertrophy, and if the hyperplastic lesion caused by stimulation is limited to one part of the mammary gland, it will cause mammary fibroma. Pregnancy. In the early stage, the epithelial buds are issued from the terminal ducts, the epithelial cells proliferate and form new lobules, the tubules increase and the lumen enlarges, thus the lobules of the mammary glands increase in size, and some of the newborn tubules can still be inserted into the adipose connective tissue, and the interstitial tissue of the lobules is edematous; in the middle stage of pregnancy, the tubules dilate, and form the glandular follicles, the epithelium of the follicles begins to have secretion activities, and the follicles turn into fat-containing cuboidal cells. The lumen of the follicle contains a small amount of secretion. In addition to capillary dilatation and congestion in the edema-like mesenchyme, lymphoid nodules can also be seen. In the middle stage, the follicular epithelium has begun to have secretory activity, the formation of lipid-containing colostral cells. And there may be colostrum secretion. In the later stage, the follicles are further enlarged, the follicular epithelium contains secretory vacuoles, and the secretion in the lumen increases. The follicles are close to each other, and the interstitium of the lobules is reduced or disappears due to pressure. Seven, lactation. After delivery, due to the decrease in the level of estrogen and progesterone, the role of prolactin is enhanced accordingly, and then by the reflex produced by the baby’s sucking, prolactin secretion is greatly increased, and under the action of prolactin, the mammary glands which have the function of lactation in the pregnancy period will be developed, and the follicular cells and the secretory ducts are secreted in large quantities, which will lead to persistent lactation. But the real lactation is more in 3?4 days after delivery, at this time the mammary gland is obviously swollen and hard, often accompanied by different degrees of pain, once you start breastfeeding, the pain is disappeared, lactation of mammary gland lobules and secretory ducts have the function of secretion and storage of milk. After breastfeeding or within a few days after interruption of breastfeeding, the mammary gland enters the recovery phase: the alveoli become hollow and atrophic, the epithelium of the alveoli disintegrates, the secretory granules within the cells disappear, the walls of the follicles and the basement membrane rupture, and they fuse with each other to form a large and irregular cystic lumen; the terminal ducts are atrophic and narrow, and the disintegrated epithelial cells are dispersed in the vicinity of the terminal ducts; there is a lymphocytic infiltration within and around the lobules; phagocytosis with fat droplets can be found in the lymphatic vessels and lymph nodes; there are also phagocytes containing phagocytes containing fat droplets; regeneration of alveolar and periductal fibrous tissue; regeneration of terminal milk ducts and appearance of young milk duct buds. The volume of the breast becomes smaller, the glands retract, the fat content decreases, the skin is looser, and the breast is generally more sagging than before, but the coloring of the nipple areola is more or less undiminished. Eight, menopause. A number of years before menopause, the mammary glands began to atrophy, glandular shrinkage, but at this time due to the thickening of fat tissue, the volume of the mammary glands, on the contrary, increased. Histologic manifestations: breast lobules are irregular, smaller and fewer in number, followed by atrophy of lobules and ducts and disappearance of epithelial cells, narrowing of the lumen of the ducts, and densification of the periductal mesenchyme. In postmenopausal geriatric mammary glands, there are usually no lobules or only a small number of lobules remain, the ducts and blood vessels may disappear, the interstitium is hardened and vitreous, and occasionally there is calcification. After understanding the development of the mammary glands and the changes they undergo throughout life, it is easy to know that breast enlargement is a normal change in the mammary glands of women of childbearing age, due to cyclical changes in hormone levels in the body, resulting in menstrual and breast cycle changes. So breast enlargement is not a disease, it is a normal physiological state. It is a normal physiological state. In general, breasts will be slightly swollen and painful before menstruation, which is also a normal manifestation. If the swelling and pain is obvious and accompanied by tingling, seriously affecting the daily life, then need to seek medical treatment. In addition, excessive mood swings can also trigger and aggravate breast tenderness. Breasts are very fragile, so protect them and do not massage them, as external force can easily damage the lobules and ducts of the breast and induce various diseases.