Nipple inversion itself is a breast deformity. Before puberty, female breasts have not yet developed and the nipples are small and flat. After puberty, as the hormone levels in the body change, menstruation begins, the breasts begin to develop, and the nipples gradually become enlarged and protruded. However, there are also many women whose nipples are partially or completely lower than the plane of the areola, or even concave inward, sinking under the skin surface, and taking on the shape of a crater. This is called nipple depression. Liao Nong, deputy director of the Plastic and Cosmetic Surgery Department of the Third Affiliated Hospital of Guangzhou Medical College, said that most of the nipple recesses are congenital, and some are caused by trauma, mastitis, etc., causing nipple muscle dysplasia, resulting in breast duct contracture and nipple retraction. In addition, wearing clothes that are too tight, especially tight underwear for women during the breast development period, affects the normal blood flow supply and normal growth and development of the breasts, especially the distal nipples, and can easily lead to nipple depression. This condition occurs in 2% of women. Usually around the age of 15, when breast development approaches adulthood, patients will find that their "breasts" are different. However, generally speaking, adolescent girls rarely come to see a doctor for this, unless there is a serious situation, such as increased nipple secretion, chronic inflammation, and a "stinky" smell. Most women who come to see a doctor only discover that inverted nipples are a big problem when they have close contact with their boyfriends. Because the nipple is a very important sexual sensitive point for women, most of women’s sexual desire requires stimulation of the nipple. Once the nipple is sunken, it will be difficult to provide effective sexual stimulation and may even affect the man's sexual desire. When meeting a girlfriend with sunken nipples, men usually feel very sorry and say, "Why are your breasts different from others?!" The woman suddenly feels that the problem is serious and goes to the hospital for treatment. Nipple depression has a certain impact on the sexual life of couples, and it will also affect breastfeeding after pregnancy. Therefore, it is best to correct it before marriage. For milder cases, you can often stretch the nipples yourself. Liao Nong reminded that girlhood is an important period for breast development, and it is also an important period for correcting nipple depression. Frequent stretching of the nipples can make the breasts protrude and increase the support of the surrounding skin, which can "shape" the breasts. When the effect of self-traction is not obvious, you should go to the hospital for consultation in time. It can be corrected through negative pressure suction or surgery. This surgery is a delicate operation, and patients should choose a plastic surgery specialist in a regular hospital for the surgery.