Yesterday, Jeff took me to Motherhood Maternity (which sells the only maternity clothing I have found to be acceptable) to get me a few more items of clothing, which were sorely needed at this point, because I can no longer fit into ANY of my pre-pregnancy clothes. We had budgeted for it, and it was nice to get cute clothes, even if I'll wear them for only a few more months. But our experience there had me wondering: "Where do really thin women buy maternity clothes?" I am not extremely slender--in fact, I'm just on the slim side of average. However, I wear size small trousers at Motherhood. I wear mostly small tops, too, although I have had to get a medium-sized sweater, thanks to some shifts in my weight distribution. So, basically, at 5'7" and 150 lbs, I am considered "small". And it's difficult to find clothes labeled with that essential S on any of the clothing racks (Maybe all the other "small" people got there before me?), but L and XL are plentiful.
Motherhood does carry petite sizes, of course, but anyone 5'5" or greater would be too tall for them.
Also of note: They do not carry brassieres, for maternity or nursing, in any size smaller than 34. Thus, any woman with a narrow back and/or small torso is probably out of luck.
So, the question remains: "Where do average-to-tall skinny women get their maternity clothes?"