I have three kids and I do not have stretch marks to this day. I started using happy event lotion from my first pregnancy. I was two weeks pregnant when I started using and continued even after giving birth. Used it with my other two kids and still no stretch marks. I love it and always recommend it to other people.
I loved the scent of this product so much and after a few weeks of use, it left my skin feeling amazingly moisturised and smooth. My stretch marks weren't reduced but, if your skin is this moisturised, I believe it would probably prevent future stretch marks.