I just gave birth to my second child a month ago and one product that I used for both my pregnancies and swear by to prevent stretch marks is the Clarins Body Treatment Oil. This stuff is really amazing. I used to apply it twice a day on the areas that were prone to stretch marks and I currently do not have a single mark on my body. I am still using it on my belly now post pregnancy as it supposedly also does a good job of firming the skin. A huge bonus is that it also smells amazing.
I would love to know what you guys love to use to prevent stretch marks.