The fabric of these sweatpants is heavyweight, soft, and comfortable, but the cut is better suited for a junior size because it has little room in the hips and buttocks.  Even then, the current sizing on the product page is of no help because it lists chest size to help fit these bottoms.  My guess is that a medium would fit a 8-10 size woman with narrow hips.  I can see these being a favorite pair of sweats/warm-ups for a teen who hasn't yet filled out.  The one thing I love, though, about the cut is the wider openings in the legs so that you can pull them on and off over running shoes.

-- Debbie Lee Wesselmann