I got stretch marks with my first, but I wasn't using anything. I was told it didn't matter, you get them or you don't, no matter what you do, and they are hereditary (my mother had them bad). That isn't quite true, although it is true for some women. My subsequent pregnancies, I have used a variety of things, most often an oil i blended myself, consisting of almond oil, vit.E oil and aloe, plus scent or whatever else struck me at the time. This time, I have just started moisturizing and I am using either coconut oil or shea butter, whichever is handy at the time. So far so good. Since my initial stretch marks years ago, I have only gotten a bit more, mostly one around my belly button which came up a few pgs back and just keeps getting bigger each time since. After you have your baby, you can try castor oil to reduce marks. Again, it's somewhat individual, but they may fade well on there own anyway - mine aren't anywhere near as visible as my mother's or some other friends, tho I haven't done much about them.
Good luck, let us know what you use and how it works out for you.