I am prone to stretch marks. I got them on my hips, butt, and thighs from puberty. I was sure I'd get them with my first pregnancy since I had them all over just from normal growth. I used Bella B Tummy Honey Butter from the beginning of my pregnancy until after it was gone after I gave birth and I didn't get one mark. I can't be sure if that's what prevented them or if I just got lucky. But I am 8 weeks with my second baby and I've already started using it in case it is! And you get a free jar the first time you order from duematernity.com. I also like their cream lotion. Their products are organic and paraben free.
I don't believe in stretch mark creams. Massage oils is what I use. From when I started showing.