Most women start getting stretch marks between 6-7 months of pregnancy, i.e. 24-28 weeks. However, the situation varies from woman to woman, as some pregnant women have stretch marks earlier, while some have stretch marks in the last 1-2 months of pregnancy, and some even have no stretch marks throughout pregnancy. The formation of stretch marks is mainly due to the hormonal influence of pregnancy, the enlargement of the uterus and the expansion of the abdomen, which causes damage or breakage of the skin elastic fibers and collagen fibers, and slowly appears irregular longitudinal cracks of pink or purple color on the skin surface. Stretch marks mainly appear on the abdominal wall, but may also appear on the inner and outer thighs, buttocks, breasts, back waist and other places, the most obvious for first-time mothers. Once they appear, stretch marks are usually difficult to remove, but they will gradually fade in the first 1-2 years after pregnancy and can be treated with laser therapy or even surgery if needed. By controlling excessive weight gain during pregnancy, the probability and extent of stretch marks can be reduced to a certain extent. Therefore, it is important to avoid a high-sugar, high-fat diet during pregnancy and to maintain moderate exercise to avoid excessive weight gain and rapid growth of abdominal circumference during pregnancy in order to reduce the breakage of subcutaneous elastic fibers in the abdomen. Pay attention to exercise before pregnancy and eat protein-rich foods in moderation, such as milk, eggs and soy products, to enhance the elasticity of the skin.