Stretch marks, officially called striae distensae (or striae gravidarum when they occur during pregnancy), are exactly what they sound like—the marks that appear on your skin when it gets stretched.
When your body rapidly grows and expands, your skin is pulled tight over the new mass that’s formed. Stretch marks are the result of your middle layer of skin or the underlying tissue tearing from being stretched so tightly. These tears become visible on the surface of your skin. While they can be unsightly and annoying, stretch marks are not harmful and don’t pose any health risks.
