Regarding stretch mark, through my Gynea and Discovery health and living, both also said it is genetic. If our mother has it, we will have it. Some may not be that obvious.
At first i also use Clarins stretch Mark Cream & Tonic Oil for the 1st 37 weeks..no stretch marks. SUDDENLY, week 38...watermelon marks came crawling up my belly. It just appearred. No itchness at all.
Oh well, so this round, i never apply. My gynea told me to apply neva milk, to ease down the mark colour, so when it heals after birth, it will not be luminous shiny, but rather closer to skin tone colour.
Hope it helps.