You can help prevent from getting stretch marks by drinking plenty of water throughout your pregnancy, and by not gaining weight too fast. Also i think keeping your skin moist by using lotions and what not will help. I don't think it's genetic at all because my mom never got any and my grandma didn't but i have sooo many stretch marks! And that is because I don't drink plenty enough water and I also gained way too much weight at once during my pregnancy
Stretchmarks donm't go away bt the dark skin returns to ur normal skin colour n they wil blend wit it too. Use bio oil n apply it after every bath n keep those strechmark moist so they don't itch
Stretch marks are mainly genetic. My boobs & thighs are the only thing that really got stretch marks. The constant shifting & growing in those areas contribute to that. Try to keep those areas well moisturized.