Science Reveals What Causes Stretch Marks — And What Treatments Do (and Don't) Work

You’re not imagining things if it seems your stretch mark cream isn’t making a dent in those pregnancy-induced indentations. A new study in the British Journal of Dermatology sheds more light on what exactly causes stretch marks — those ​recesses in your skin, also known as striae gravidarum, which ​affect 50 to​ 90 percent of women — and why most topical treatments don’t effectively tackle the problem.

Researchers examined skin samples from 27 pregnant women who had developed fresh, reddish stretch marks around the second trimester and compared the stretch-marked areas to nearby stretched skin on the abdomen and to less-stretched skin on the hip. They found that the elastic fiber network in the dermis, which is the inner layer of skin, was damaged. “Elastic fibers are part of the connective tissue of the skin and help give skin its elastic properties, or its ability to return to its original shape after being pulled or stretched,” Frank Wang, M.D., the lead author of the study and assistant professor in the department of dermatology at the University of Michigan, tells Yahoo Parenting.

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The body tries to repair the damage, but isn’t able to do an adequate job, notes Wang. That leads to lax skin and those telltale grooves post-pregnancy. Wang points out that nearly all topical treatments aren’t equipped to repair the damage to the skin’s elastic fibers.

“There are hundred of thousand of creams out there, but the problem with a lot of them is that they are not necessarily based on the science behind stretch marks,” he says. “That’s probably why a lot of them don’t work. They’re not based on the science behind stretch marks’ formation.”

But if you’re bothered by your stretch marks, that doesn’t mean you’re necessarily stuck with them. While nothing will miraculously bring back your pre-pregnancy skin, Wang points out that one prescription cream, tretinoin (aka retinoic acid), helps reduce reddish stretch marks and has scientific evidence to back it up. “Tretinoin can cause skin irritation and you typically have to use it for six months to see results, but it can help replenish some of the collagen lost,” says Wang. “It may help fill in [the grooves].” However, Tretinoin is not recommend for use during pregnancy or breastfeeding, so you’ll have to wait to start treatment until you’ve weaned your baby.

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Another option: Laser treatments. “Lasers are definitely used to improve the appearance of stretch marks,” says Wang. “Some lasers can help target the redness of stretch marks, while others can be used more for improving the texture of stretch marks.”

Just be sure to check your expectations — and your wallet. Wang warns: “At best, they partially improve the appearance of the lesions, and they are costly. Don’t expect 100 percent improvement.”

(Photo: Jennifer Boggs/Amy Paliwoda/Getty Images)

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