What are stretch marks?

Everyone has skin that’s genetically predisposed to withstand a certain tensile load or amount of stretching and tightening. If you gain weight during a growth spurt or pregnancy, your skin will stretch as far as it can and then begin to tear through the collagen and elastin fibers that give your skin shape, texture, and elasticity. However, the size of your baby and the amount of postpartum weight loss are other factors that play a role in the appearance of stretch marks. “Some women heal these tears with beautiful scars and you can hardly see them, while others heal with bad scars,” says Stephen Mulholland, a plastic surgeon based in Toronto. “The difference is in your DNA and the quality and resiliency of your collagen. Ultimately, you’re fighting the genetic code of your parents and what they gave you.”