oil and stretch marks...

So I'm 27 weeks and no stretch marks yet. I have used bio oil religiously and started using coconut oil. I drink a ton of water and neither my mother or grandma had stretch marks but trying to take caution. I do have white ones from gaining and losing in the past which I know are from a long time ago. Now the question is should I continue to use bio oil or just switch to coconut oil or stay with both?