When I was pregnant I made a home-made concoction that I put on my stomach several times a day–morning, night, before showers, etc. I have had stretch marks in the past and so my body does get them. Also, my baby was big–and I my stomach was huge! I didn’t get any stretch marks with my pregnancy so I think this may have helped.
I thought I’d share my recipe: one part coconut oil (you can get this at Whole Foods, etc–it solidifies in cold temps), one part olive oil and then I threw in vitamin A, E and some essential oils that I like. I also added almond oil to one batch. This is oily, so it doesn’t work if you’re going to immediately put on a nice top–but it’s great for night, or when you don’t mind if some oil gets on your shirt. I also put it on before showers, so it could go in my skin w/the heat and steam.