Wedding dress and weight loss

Has any one brought their wedding dress in the size they was and lost loads of weight and able to get it taken in to their new weight?
Been worried about it cause it's a lot of money to get a new dress.

I haven't got my dress yet but from what I have heard from other brides, depending on the style of the dress they can be altered plus or minus four dress sizes. Any more than that the dress can lose it's original shape and design.