I have been told this aswell.. But you also have to look at all the beautiful larger woman out there that have fallen pregnant straight away that didn't have any problems..
Alan's aunt is very overweight, but has conceived naturally 4 gorgeous children.
My nanna was the same and a lot of my dad's side aunts aswell...

I know I have to lose weight before I go and start TTC again, but there are a lot of woman out there who have done it my size.