Stretch marks are mainly due to the hormonal effects of pregnancy, combined with the expansion of the abdomen, causing damage or breakage of the elastic and collagen fibers of the skin, and the thinning of the abdominal skin and the appearance of the pattern. After childbirth, these patterns will gradually disappear, leaving behind white or silvery-white shiny scar lines, known as stretch marks. I. Characteristics and distribution of stretch marks Stretch marks are characterized by different widths and lengths, pink or purplish red before delivery, white or silvery white after delivery, wavy and irreversible. They are generally found on the abdominal wall, inner and outer thighs, buttocks, chest, back waist, arms and other parts of the body, and are easy to identify. The time of the appearance of stretch marks varies due to the different body types of pregnant women. In general, some pregnant women will have stretch marks after 5-6 months of pregnancy, and some of them will appear in late pregnancy or in January before delivery. Some pregnant women have a better constitution and will not even have stretch marks throughout their pregnancy. How to prevent stretch marks Stretch marks do not necessarily appear on every pregnant woman, and the following measures will help prevent their appearance: 1, balanced diet: during pregnancy should be rich in vitamins and minerals, eat more vegetables and fruits; 2, reasonable control of weight gain: pregnancy weight gain should not exceed 2 kg per month, the entire pregnancy should be controlled at 11-14 kg; 3, appropriate Use belly brace: belly brace can assist to bear the burden of gravity of the abdomen and slow down the excessive stretching and pulling of the skin; 4, pay attention to exercise: adhere to the cold water rubbing bath to enhance the elasticity of the skin.