Human skin contains many tiny elastic fibers and reticular fibers. Under normal circumstances, skin elastic fibers maintain a certain tension with muscles and have a certain elasticity. Australian medical experts have found that 90% of pregnancy is caused by the adrenal gland secreting a large amount of glucocorticoid during pregnancy, which increases the brittleness of skin elastic fibers and collagen fibers. When the elasticity of skin elastic fibers and collagen fibers reaches a certain limit, they will break and form stretch marks.
When a woman is pregnant for more than 3 months, the enlarged uterus protrudes from the pelvic cavity and develops into the abdominal cavity, and the abdomen begins to swell. Under the influence of the enlarged uterus, the skin elastic fibers and abdominal muscles began to elongate. Especially after six months of pregnancy. Beyond a certain limit, the elastic fibers of the skin are broken and the tendons of rectus abdominis are separated to varying degrees. As a result, pink or purple irregular longitudinal cracks appeared on the abdominal skin. After delivery, although the broken elastic fiber is gradually repaired, it is difficult to return to the previous state, and the cracks on the original skin gradually fade, and finally become silvery white, resulting in stretch marks.
Reason: There are many layers in human abdomen from outside to inside, which are skin, skin elastic fibers, subcutaneous fat layer, rectus abdominis composed of muscle fiber group and tendon, preperitoneal fat layer and peritoneum. Under normal circumstances, the skin elastic fibers and rectus abdominis maintain certain elasticity and freely expand and contract within certain limits. When a woman is pregnant for more than 3 months, the enlarged uterus protrudes from the pelvic cavity and develops into the abdominal cavity, and the abdomen begins to swell. Under the influence of the enlarged uterus, the skin elastic fibers and abdominal muscles began to elongate. Especially after six months of pregnancy. Beyond a certain limit, the elastic fibers of the skin are broken and the tendons of rectus abdominis are separated to varying degrees. As a result, pink or purple irregular longitudinal cracks appeared on the abdominal skin. After delivery, although the broken elastic fiber is gradually repaired, it is difficult to return to the previous state, and the original cracks on the skin gradually fade away, and finally become silvery white, that is, stretch marks.
The appearance of stretch marks is related to physical fitness. Not every pregnant woman will have stretch marks, and the severity of stretch marks varies from person to person. The most common part of stretch marks is the abdomen. The formation position and color of stretch marks. Stretch marks appear in the lower abdomen, thighs, buttocks, chest or back during pregnancy, showing purple or pink stripes. According to statistics, about 70% ~ 90% pregnant women will have stretch marks when they are pregnant for the first time, which makes women who love beauty very upset.
When the local skin is stretched and thinned, the walls of capillaries and veins in the dermis will also expand and become thinner, exposing the color of blood, and the skin stripes will be purple or pink. After delivery, the broken elastic fiber can be slowly repaired, the capillary and vein walls in the dermis will gradually thicken, and the color of skin stripes will gradually fade to white or silvery white, but it can't completely return to the skin state without cracks before pregnancy. It is best to speed up the repair with the help of stretch marks repair products.
During pregnancy, due to the continuous growth of the fetus and the continuous expansion of the abdomen, the skin of the abdomen is overstretched, and many collagen fibers under the skin are finally "torn off", which makes the skin form a special type of scar. In fact, stretch marks are just one of the most common skin edema lines. Some children in the growth and development period, due to the rapid growth, legs and waist can also appear different degrees of edema lines.