What are striae?
Striae or stretch marks are linear scars that occur when the subcutaneous connective tissue is pulled apart by rapid growth of the stomach. They can also appear on the breasts and the top of your thighs.
With a fast-growing belly, the elastic and collagen fibers of the deeper layers of the skin can tear. Especially in the third trimester of pregnancy, the risk of getting striae is greatest because the size of the belly reaches its peak. Pregnancy stripes can certainly not be harmful, but they are annoying. Once you have the marks, they will generally be present for a lifetime.
Unfortunately, the striae will not disappear. They leave a kind of pearl-white scar, which remains visible after pregnancy, even if you get to the weight before you were pregnant. The scars may get smaller and the color may change slightly, but this may take years. Research has shown that younger, or paler skin may be more susceptible to stretch marks.
Prevent pregnancy striations
From Oliver In Pregnancy