Do any creams work to reduce stretch marks?

Stretch marks. Not really. Stretch marks are torn elastic fibers in the skin followed by inflammation. Some people feel tha Mederma for stretch marks may help. Time alone with improve them and the pulsed dye laser can be used to speed up improvement of the redness.
Not really. There are no magic creams that get rid of striae. Tretinoin and other retinoid creams have been used, but the visible effect is not very significant.
Yes. Many over-the-counter products claim to "treat" stretch marks, such as cocoa butter, vitamin E cream, etc. One particular product has done clinical trials and has some data to document improvement in post-pregnancy "striae, " or stretch marks. The product is called mederma, and does not require a prescription. Follow label instructions and use for 8 - 12 weeks.