1. Early childhood: at birth, the nipple is depressed, and the areola is also formed. There is a ductal acinar system with 15~20 leaves, and its acinar contains a small amount of colostrum (stimulated by maternal estrogen, the fetal mammary gland secretes fluid. However, it will be discharged from the nipple within one week after birth, and it will last for three to four weeks after delivery, and the acinar tissue will quickly degenerate into ductal tissue. In infancy and childhood, breasts rarely develop.
2. Adolescence: When girls are ten to twelve years old, the hypothalamus begins to secrete gonadotropins, which leads to the secretion of gonadotropins by the pituitary gland, and further stimulates the secretion of estrogen and lutein by the ovaries. Estrogen stimulates mammary duct development, while progesterone stimulates acinar development, resulting in rapid growth of adolescent mammary tissue. Generally, the breast development in adolescence is divided into five stages. A. the first stage: nipple protrusion. B. The second stage: from the age of ten to twelve, the breasts begin to develop, the areola becomes bigger, and the breasts form hills. C. Stage III: About thirteen to fourteen years old, nipples and breasts continue to develop. D. Stage 4: At the age of fourteen to fifteen, the areola and nipple begin to bulge, and the breasts gradually become spherical. E. Stage 5: After the age of fifteen, the breasts gradually mature and finalize the design.
3. Pregnancy: The most obvious change within a few weeks after conception is breast enlargement that lasts for the whole pregnancy. In the early pregnancy, the blood vessels in the breast increase and the superficial veins become obvious, usually accompanied by pain and itching. In addition, the nipple of areola will become bigger and darker. The change of breast tissue is the proliferation of duct molecules and acinar cells, which leads to the growth and branching of ducts, which can reach several times that of non-pregnancy
From the second trimester of pregnancy, the proliferation of acinar cells gradually decreased and replaced by cell differentiation. From the second trimester of pregnancy, acinar cells gradually become monolayer secretory cells, so in the second trimester of pregnancy, a small amount of yellowish liquid can be seen in the acinar cavity, which is called colostrum. Breast swelling continues throughout pregnancy, because cells have been differentiating and developing, and the secretion of acinar cells has been increasing.
Breast, like endometrium, will be affected by female hormones and will change. Understanding and caring for this changeable organ requires more patience.
When a girl enters puberty, her breasts develop first. After puberty, under the influence of estrogen in the body, girls' breasts begin to develop. At this time, in addition to the continuous development of many slender mammary ducts, a lot of fat has accumulated in the breast. Because the breast tissue is hard and the adipose tissue is soft, the breast bulges and is elastic, which becomes a symbol of women's maturity. The situation of breast development, such as breast size, symmetry, development sooner or later, abnormal development, etc., has become the source of girls' youth troubles.
There are great individual differences in the breast development of female students. Some girls start to develop breasts when they are only 8 or 9 years old, and some girls don't start to develop breasts until they are over 16 years old. Most girls begin to develop breasts before menarche, about 9- 14 years old. At the beginning of breast development, the mammary gland and its surrounding adipose tissue form a button-like protuberance on the nipple and its surrounding areola, which makes the nipple and areola bulge and the nipple begin to grow. Then the nipple bulge becomes more obvious, gradually becomes fuller, and finally develops into the shape of an adult breast. The speed of breast development varies from person to person. Some girls' breasts develop later, but faster, and some girls' breasts develop earlier, but slower.
Girls with early breast development often feel embarrassed and annoyed, and try to hide their breasts to escape. When walking, bow your head and hold your chest, or wear tights to tighten your chest, which limits the normal development of breasts and breasts. However, the practice of corset will oppress the breasts and nipples, and the mammary gland will be stunted, which will cause difficulties in breastfeeding and lactation in the future, and it is also easy to cause breast diseases. In essence, girls with larger breasts develop earlier, which is also influenced by many factors. Some girls are obese, and their breasts will become fuller. Some girls are affected by genetic factors, nutritional conditions and climate, but usually the development of breasts will stop after a certain age. Large breasts have no adverse effects on the body, nor can they reflect a person's ideological and moral consciousness, so there is no need to worry about the development of breasts.
There are also some girls who are worried and uneasy that their breasts have not yet begun to develop or become smaller. More sensitive girls, in public toilets or group activities, it is easy to find that their breasts are not as plump as some peers. They may doubt whether their breasts are developing normally, or they may worry whether their fertility will be affected in the future.
The size of breast development is not only influenced by hormones, but also by heredity, environmental factors, nutritional status, obesity, physical exercise and other factors. Small breasts may also be related to development sooner or later. In fact, as long as the development of reproductive organs and menstruation are normal, it will not affect the breastfeeding function and fertility of adults. Generally speaking, the development of breasts will not affect the development speed in the future, nor will it affect the size and shape of breasts after adulthood, so there is no need to worry about late development and small breasts. Of course, if the breast does not develop for a long time after menarche, you should go to the hospital for examination and ask the doctor to diagnose whether it is physiological or pathological, so as to take countermeasures.
Women's breasts are not necessarily exactly the same, but they are about the same size. During the development of some girls' breasts, there will also be an imbalance between left and right development, which is often slightly larger and smaller, or slightly higher and lower. In terms of physiological development, the response of left and right breasts to estrogen is inconsistent, and the breast with active gland hyperplasia is larger. The inconsistency between the size of the left and right breasts has no effect on future fertility and sexual function, and it is not harmful to health. Especially in adolescence, it may be normal for one breast to develop or one breast to develop faster than the other. When it matures, the two breasts will be the same size. Adult girls will also notice that their breasts are different in size, but the difference is not obvious, and often no one will notice them except themselves. However, as an adult, if the breast size difference between the two sides is particularly large, you should go to the hospital for consultation.
Adolescent girls should learn some health knowledge about breast development and health care, and correctly treat physiological phenomena in the normal development process. Girls who are worried about breast size in adolescence should not take measures to tighten their breasts or increase them, so as not to affect the normal development of their breasts.