I used Palmers Cocoa Butter all through my pregnancy and stretch marks started to show at 32wks and just kept getting worse.

My sister never used anything and has no stretch marks after 2 pregnancy's.

My mum also didnt use anything and only got stretch mark when she was pregnant with #4.

I think if your going to get them then you really cant stop it from happening, only help the fading process along afterwards. (im too lazy!!)