I used all the butters, oils & creams I read about stretch marks, because I was horrified by the thought of having them!! And I used them religiously, every day of my pregnancy and continued, till my babies were 6 months old!! I was carrying twins, I was 135 lbs before I got pregnant and 235 lbs at 34 weeks, which is when I delivered my healthy & beautiful twins ...
Just like yours, for first 6 months of my pregnancy, no stretch marks and I gave the creams all the credit!! But then, the belly stretched, the skin tore, the purplish, pinkish, reddish marks appeared .... and they came in all directions .... under the belly, on the sides, on the top of the belly, under the boobs, on the sides of the boobs .... oh my gosh!!! I couldn't believe it was happening to me!!
Thank God, I delivered early at 34 weeks .... I was estatic to see my twins, but I couldn't get over my stretch marks .... I did some intensive research of my own ... the conclusion is:
If you are religiously using creams & butters & oils and you do not get stretch marks, you believe it is the cosmetics that saved your belly!
But if you use the same products religiously, and get the stretch marks anyway, you know the bitter truth ...
its 35% genetic + it also depends 35% on the elasticity of your skin (how much you exercised before) + it depends 30% on how much weight you gain.
Stretch marks are your marks of victory ... of big accomplishments .... I know you would rather do without them, but if you are having them, they are here to stay, unless you prefer to put yourself through some skin grafting ....
BTW, it took me about 2.5 years to get used to them, to get over them, and now they are a part of ME, and I am rather proud of them .... when I go swimming, they speak for themselves ... ;)
my bigger problem is the broken naval ring ... I am going to get it fixed this year .... but a wonderful side effect of breastfeeding are my wonder boobs!!
so ... gain some, lose some ... thats the universal law.