They say that by this point in my pregnancy, I should have gained 10 - 13 pounds. The books that I have do not say this can vary widely between women. I think it's a ploy to make us nervous.
To this date, I've lost two pounds and gained three. I, however, will not listen to the books. If my doctor shows concern, then I will be concerned. I also think it's time to find some new books.