Mustela Stretch Marks Double Action Cream, $41

Doctors suggest avoiding possibly harmful ingredients while you're pregnant -- even if the research is inconclusive. Parabens and phthalates top the list since they have been linked to everything from breast cancer to diabetes. Look for products with natural ingredients like this one from Mustela (as well as the other ones we included in this roundup).

According to Mustela's research, the avocado peptides in this stretch mark cream can help stimulate collagen production by 60 percent. It also contains an ingredient derived from the Larch tree that minimizes inflammation. Of course you can't just buy a tube and slather some on every now and then -- Mustela recommends massaging it in circular motions two to three times a day.

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