I'm no expert at preventing stretch marks but I have done a lot of research even before I was pregnant to try and figure out how to prevent them in any way I could. I got a couple on my thighs a few years ago and they've been my arch enemy ever since.
When I first found out I was pregnant I was using coconut oil religiously. Morning, afternoon, and night, and although I still think coconut oil is very beneficial, I felt like I needed something thicker to really moisturize. A few weeks ago I was at my local Motherhood store and the nice lady working informed me that a lot of products out there that claim to prevent stretch marks have mineral oil in them. Mineral oil actually puts a layer on your skin and prevents the other beneficial ingredients from penetrating into your skin. One popular brand that has mineral oil in it is Palmers Cocoa Butter Formula. If you've used this and it worked for you then thats great but I'd rather be safe than sorry!
I also know that a lot about getting stretch marks has to do with your DNA and skin elasticity but moisturizing and oiling that belly won't hurt, so why not! I'm only sixteen weeks so I can't necessarily vouch for these products completely but they seem to be working at keeping my skin highly moisturized and firm and they seem to have great reviews. I will update you when I'm further along on my stretch mark status. Also make sure to drink tons of water!
What to use:
Both products smell great which makes them very pleasant to use. I use the body butter in the morning and the oil at night.
What not to use:
Any product containing mineral oil. I know Palmers Cocoa Butter Formula and even Honest Organic Belly Balm contain mineral oil. I'm not sure which other products do, just check the ingredients on the back.
What worked for you? Let me know in the comments below!