Stretch marks are mostly genetic factor, if your skin is low in elastin or collagen, you will be more prone to having them appear.
During pregnancy I drank lots of water, and took vitamin E, (& still got a few), but nothing compaired to other girls after 3 pregnancies, my mom had 7 kids & not one stretch mark, so I guess genetics has a lot to do with it.
As far as creams go, if your planning on using one, amke sure that it contains: vitamin E, collagen and possibly cocoa butter.