I bought this for my daughter in XS which was supposed to fit size 2-4 and should have been perfect for her.  When she first put it on she was delighted, but once she got to her ballet class it became clear that there was just not enough stretch left and the leotard was uncomfortable to dance in.  Rather than pay to return it (I live in the Middle East) I simple ordered another leotard in the next size up and this fitted perfectly.