I think maldorf hit it on the head for the most part. Either you get them and nothing helps, or you get them and some times stuff helps, or best of all you don't!
I get them bad, and I have stretch marks from being 305 FAT pds, to going down to 170 and growing back to 240 and now going back down to 200. so much weight fluctuation for me I knew it was inevitable. One thing for sure my new stretch marks are from growing big!